GUARANTORS OF SECURITIES (Condensed Balance Sheet) (Details) - USD ($) $ / shares in Units, $ in Thousands |
Jun. 30, 2019 |
Mar. 31, 2019 |
Dec. 31, 2018 |
Jun. 30, 2018 |
Mar. 31, 2018 |
Dec. 31, 2017 |
Current assets: |
|
|
|
|
|
|
|
|
Cash and cash equivalents |
$ 88,430
|
[1] |
|
$ 50,753
|
[1] |
$ 15,057
|
|
$ 13,583
|
Receivables: |
|
|
|
|
|
|
|
|
Trade, operating, net of allowance for doubtful accounts |
30,493
|
|
|
33,306
|
|
|
|
|
Trade, dry-leasing |
5,165
|
|
|
3,803
|
|
|
|
|
Tax receivables |
2,680
|
|
|
3,187
|
|
|
|
|
Other |
16,478
|
|
|
2,343
|
|
|
|
|
Inventories, net |
21,004
|
|
|
20,673
|
|
|
|
|
Prepaid expenses |
2,822
|
|
|
1,807
|
|
|
|
|
Total current assets |
167,072
|
|
|
115,872
|
|
|
|
|
Property and equipment |
918,972
|
|
|
917,161
|
|
|
|
|
Accumulated depreciation |
(336,825)
|
|
|
(317,967)
|
|
|
|
|
Property and equipment, net |
582,147
|
|
|
599,194
|
|
|
|
|
Operating lease right-of-use |
8,080
|
|
|
|
|
|
|
|
Equity investments and advances |
0
|
|
|
27,112
|
|
|
|
|
Investments in consolidated subsidiaries |
0
|
|
|
0
|
|
|
|
|
Intangible assets |
1,098
|
|
|
1,107
|
|
|
|
|
Deferred income taxes |
0
|
|
|
0
|
|
|
|
|
Intercompany receivables |
0
|
|
|
0
|
|
|
|
|
Other assets |
6,487
|
|
|
21,578
|
|
|
|
|
Total assets |
764,884
|
|
|
764,863
|
|
|
|
|
Current liabilities: |
|
|
|
|
|
|
|
|
Accounts payable and accrued expenses |
13,467
|
|
|
13,161
|
|
|
|
|
Accrued wages and benefits |
8,222
|
|
|
9,267
|
|
|
|
|
Accrued interest |
536
|
|
|
569
|
|
|
|
|
Accrued income taxes |
938
|
|
|
973
|
|
|
|
|
Accrued other taxes |
1,410
|
|
|
1,268
|
|
|
|
|
Accrued contingencies |
647
|
|
|
630
|
|
|
|
|
Current portion of long-term debt |
1,859
|
|
|
2,058
|
|
|
|
|
Other current liabilities |
2,902
|
|
|
878
|
|
|
|
|
Total current liabilities |
29,981
|
|
|
28,804
|
|
|
|
|
Long-term debt |
158,981
|
|
|
160,217
|
|
|
|
|
Deferred income taxes |
106,929
|
|
|
108,357
|
|
|
|
|
Intercompany payables |
0
|
|
|
0
|
|
|
|
|
Operating lease liabilities |
6,387
|
|
|
|
|
|
|
|
Other liabilities |
850
|
|
|
747
|
|
|
|
|
Total liabilities |
303,128
|
|
|
298,125
|
|
|
|
|
Redeemable noncontrolling interest |
3,094
|
|
$ 3,160
|
3,302
|
|
3,466
|
$ 3,603
|
3,766
|
Equity: |
|
|
|
|
|
|
|
|
Common stock, $0.01 par value, 60,000,000 shares authorized; 21,419,462 and 21,765,404 outstanding in 2019 and 2018, respectively, exclusive of treasury shares |
224
|
|
|
219
|
|
|
|
|
Additional paid-in capital |
449,687
|
|
|
447,298
|
|
|
|
|
Retained earnings |
17,282
|
|
|
18,285
|
|
|
|
|
Treasury shares, at cost; 958,481 and 156,737 shares in 2019 and 2018, respectively |
(8,531)
|
|
|
(2,476)
|
|
|
|
|
Accumulated other comprehensive income, net of tax |
0
|
|
|
110
|
|
|
|
|
Total equity |
458,662
|
|
$ 458,885
|
463,436
|
|
$ 436,048
|
$ 445,716
|
$ 445,681
|
Total liabilities, redeemable noncontrolling interest and stockholders’ equity |
764,884
|
|
|
764,863
|
|
|
|
|
Allowance for doubtful accounts, trade receivables |
$ 139
|
|
|
$ 261
|
|
|
|
|
Common stock, par value (in dollars per share) |
$ 0.01
|
|
|
$ 0.01
|
|
|
|
|
Common stock, shares authorized (in shares) |
60,000,000
|
|
|
60,000,000
|
|
|
|
|
Common stock, shares outstanding (in shares) |
21,419,462
|
|
|
21,765,404
|
|
|
|
|
Treasury shares (in shares) |
958,481
|
|
|
156,737
|
|
|
|
|
Reportable Legal Entities | Parent |
|
|
|
|
|
|
|
|
Current assets: |
|
|
|
|
|
|
|
|
Cash and cash equivalents |
$ 83,584
|
|
|
$ 48,396
|
|
|
|
|
Receivables: |
|
|
|
|
|
|
|
|
Trade, operating, net of allowance for doubtful accounts |
0
|
|
|
0
|
|
|
|
|
Trade, dry-leasing |
0
|
|
|
0
|
|
|
|
|
Tax receivables |
0
|
|
|
0
|
|
|
|
|
Other |
0
|
|
|
0
|
|
|
|
|
Inventories, net |
0
|
|
|
0
|
|
|
|
|
Prepaid expenses |
756
|
|
|
398
|
|
|
|
|
Total current assets |
84,340
|
|
|
48,794
|
|
|
|
|
Property and equipment |
0
|
|
|
0
|
|
|
|
|
Accumulated depreciation |
0
|
|
|
0
|
|
|
|
|
Property and equipment, net |
0
|
|
|
0
|
|
|
|
|
Operating lease right-of-use |
0
|
|
|
|
|
|
|
|
Equity investments and advances |
|
|
|
0
|
|
|
|
|
Investments in consolidated subsidiaries |
181,684
|
|
|
172,950
|
|
|
|
|
Intangible assets |
0
|
|
|
0
|
|
|
|
|
Deferred income taxes |
10,602
|
|
|
9,904
|
|
|
|
|
Intercompany receivables |
317,076
|
|
|
366,541
|
|
|
|
|
Other assets |
961
|
|
|
1,251
|
|
|
|
|
Total assets |
594,663
|
|
|
599,440
|
|
|
|
|
Current liabilities: |
|
|
|
|
|
|
|
|
Accounts payable and accrued expenses |
137
|
|
|
136
|
|
|
|
|
Accrued wages and benefits |
5
|
|
|
43
|
|
|
|
|
Accrued interest |
469
|
|
|
500
|
|
|
|
|
Accrued income taxes |
918
|
|
|
918
|
|
|
|
|
Accrued other taxes |
0
|
|
|
0
|
|
|
|
|
Accrued contingencies |
0
|
|
|
0
|
|
|
|
|
Current portion of long-term debt |
0
|
|
|
0
|
|
|
|
|
Other current liabilities |
998
|
|
|
647
|
|
|
|
|
Total current liabilities |
2,527
|
|
|
2,244
|
|
|
|
|
Long-term debt |
133,496
|
|
|
133,900
|
|
|
|
|
Deferred income taxes |
0
|
|
|
0
|
|
|
|
|
Intercompany payables |
0
|
|
|
0
|
|
|
|
|
Operating lease liabilities |
0
|
|
|
|
|
|
|
|
Other liabilities |
0
|
|
|
0
|
|
|
|
|
Total liabilities |
136,023
|
|
|
136,144
|
|
|
|
|
Redeemable noncontrolling interest |
0
|
|
|
0
|
|
|
|
|
Equity: |
|
|
|
|
|
|
|
|
Common stock, $0.01 par value, 60,000,000 shares authorized; 21,419,462 and 21,765,404 outstanding in 2019 and 2018, respectively, exclusive of treasury shares |
224
|
|
|
219
|
|
|
|
|
Additional paid-in capital |
449,688
|
|
|
447,299
|
|
|
|
|
Retained earnings |
17,259
|
|
|
18,254
|
|
|
|
|
Treasury shares, at cost; 958,481 and 156,737 shares in 2019 and 2018, respectively |
(8,531)
|
|
|
(2,476)
|
|
|
|
|
Accumulated other comprehensive income, net of tax |
|
|
|
0
|
|
|
|
|
Total equity |
458,640
|
|
|
463,296
|
|
|
|
|
Total liabilities, redeemable noncontrolling interest and stockholders’ equity |
594,663
|
|
|
599,440
|
|
|
|
|
Reportable Legal Entities | Guarantors |
|
|
|
|
|
|
|
|
Current assets: |
|
|
|
|
|
|
|
|
Cash and cash equivalents |
0
|
|
|
0
|
|
|
|
|
Receivables: |
|
|
|
|
|
|
|
|
Trade, operating, net of allowance for doubtful accounts |
23,151
|
|
|
27,509
|
|
|
|
|
Trade, dry-leasing |
5,165
|
|
|
3,803
|
|
|
|
|
Tax receivables |
10
|
|
|
6
|
|
|
|
|
Other |
16,336
|
|
|
1,949
|
|
|
|
|
Inventories, net |
20,962
|
|
|
20,633
|
|
|
|
|
Prepaid expenses |
1,778
|
|
|
1,219
|
|
|
|
|
Total current assets |
67,402
|
|
|
55,119
|
|
|
|
|
Property and equipment |
902,246
|
|
|
900,611
|
|
|
|
|
Accumulated depreciation |
(332,872)
|
|
|
(314,567)
|
|
|
|
|
Property and equipment, net |
569,374
|
|
|
586,044
|
|
|
|
|
Operating lease right-of-use |
7,028
|
|
|
|
|
|
|
|
Equity investments and advances |
|
|
|
27,112
|
|
|
|
|
Investments in consolidated subsidiaries |
0
|
|
|
0
|
|
|
|
|
Intangible assets |
0
|
|
|
0
|
|
|
|
|
Deferred income taxes |
0
|
|
|
0
|
|
|
|
|
Intercompany receivables |
0
|
|
|
0
|
|
|
|
|
Other assets |
5,421
|
|
|
20,231
|
|
|
|
|
Total assets |
649,225
|
|
|
688,506
|
|
|
|
|
Current liabilities: |
|
|
|
|
|
|
|
|
Accounts payable and accrued expenses |
11,375
|
|
|
11,357
|
|
|
|
|
Accrued wages and benefits |
6,621
|
|
|
7,743
|
|
|
|
|
Accrued interest |
67
|
|
|
69
|
|
|
|
|
Accrued income taxes |
10
|
|
|
6
|
|
|
|
|
Accrued other taxes |
1,034
|
|
|
768
|
|
|
|
|
Accrued contingencies |
0
|
|
|
0
|
|
|
|
|
Current portion of long-term debt |
1,663
|
|
|
1,663
|
|
|
|
|
Other current liabilities |
1,438
|
|
|
220
|
|
|
|
|
Total current liabilities |
22,208
|
|
|
21,826
|
|
|
|
|
Long-term debt |
25,485
|
|
|
26,317
|
|
|
|
|
Deferred income taxes |
116,285
|
|
|
117,015
|
|
|
|
|
Intercompany payables |
253,989
|
|
|
310,727
|
|
|
|
|
Operating lease liabilities |
5,793
|
|
|
|
|
|
|
|
Other liabilities |
850
|
|
|
720
|
|
|
|
|
Total liabilities |
424,610
|
|
|
476,605
|
|
|
|
|
Redeemable noncontrolling interest |
3
|
|
|
3
|
|
|
|
|
Equity: |
|
|
|
|
|
|
|
|
Common stock, $0.01 par value, 60,000,000 shares authorized; 21,419,462 and 21,765,404 outstanding in 2019 and 2018, respectively, exclusive of treasury shares |
0
|
|
|
0
|
|
|
|
|
Additional paid-in capital |
100,307
|
|
|
100,306
|
|
|
|
|
Retained earnings |
124,305
|
|
|
111,482
|
|
|
|
|
Treasury shares, at cost; 958,481 and 156,737 shares in 2019 and 2018, respectively |
0
|
|
|
0
|
|
|
|
|
Accumulated other comprehensive income, net of tax |
|
|
|
110
|
|
|
|
|
Total equity |
224,612
|
|
|
211,898
|
|
|
|
|
Total liabilities, redeemable noncontrolling interest and stockholders’ equity |
649,225
|
|
|
688,506
|
|
|
|
|
Reportable Legal Entities | Non-guarantors |
|
|
|
|
|
|
|
|
Current assets: |
|
|
|
|
|
|
|
|
Cash and cash equivalents |
4,846
|
|
|
2,357
|
|
|
|
|
Receivables: |
|
|
|
|
|
|
|
|
Trade, operating, net of allowance for doubtful accounts |
7,342
|
|
|
5,797
|
|
|
|
|
Trade, dry-leasing |
0
|
|
|
0
|
|
|
|
|
Tax receivables |
2,670
|
|
|
3,181
|
|
|
|
|
Other |
142
|
|
|
394
|
|
|
|
|
Inventories, net |
42
|
|
|
40
|
|
|
|
|
Prepaid expenses |
288
|
|
|
190
|
|
|
|
|
Total current assets |
15,330
|
|
|
11,959
|
|
|
|
|
Property and equipment |
16,726
|
|
|
16,550
|
|
|
|
|
Accumulated depreciation |
(3,953)
|
|
|
(3,400)
|
|
|
|
|
Property and equipment, net |
12,773
|
|
|
13,150
|
|
|
|
|
Operating lease right-of-use |
1,052
|
|
|
|
|
|
|
|
Equity investments and advances |
|
|
|
0
|
|
|
|
|
Investments in consolidated subsidiaries |
0
|
|
|
0
|
|
|
|
|
Intangible assets |
1,098
|
|
|
1,107
|
|
|
|
|
Deferred income taxes |
0
|
|
|
0
|
|
|
|
|
Intercompany receivables |
171
|
|
|
0
|
|
|
|
|
Other assets |
105
|
|
|
96
|
|
|
|
|
Total assets |
30,529
|
|
|
26,312
|
|
|
|
|
Current liabilities: |
|
|
|
|
|
|
|
|
Accounts payable and accrued expenses |
1,955
|
|
|
1,668
|
|
|
|
|
Accrued wages and benefits |
1,596
|
|
|
1,481
|
|
|
|
|
Accrued interest |
0
|
|
|
0
|
|
|
|
|
Accrued income taxes |
10
|
|
|
49
|
|
|
|
|
Accrued other taxes |
376
|
|
|
500
|
|
|
|
|
Accrued contingencies |
647
|
|
|
630
|
|
|
|
|
Current portion of long-term debt |
196
|
|
|
395
|
|
|
|
|
Other current liabilities |
466
|
|
|
11
|
|
|
|
|
Total current liabilities |
5,246
|
|
|
4,734
|
|
|
|
|
Long-term debt |
0
|
|
|
0
|
|
|
|
|
Deferred income taxes |
1,246
|
|
|
1,245
|
|
|
|
|
Intercompany payables |
63,280
|
|
|
55,847
|
|
|
|
|
Operating lease liabilities |
594
|
|
|
|
|
|
|
|
Other liabilities |
0
|
|
|
27
|
|
|
|
|
Total liabilities |
70,366
|
|
|
61,853
|
|
|
|
|
Redeemable noncontrolling interest |
3,091
|
|
|
3,299
|
|
|
|
|
Equity: |
|
|
|
|
|
|
|
|
Common stock, $0.01 par value, 60,000,000 shares authorized; 21,419,462 and 21,765,404 outstanding in 2019 and 2018, respectively, exclusive of treasury shares |
0
|
|
|
0
|
|
|
|
|
Additional paid-in capital |
4,561
|
|
|
4,562
|
|
|
|
|
Retained earnings |
(47,489)
|
|
|
(43,402)
|
|
|
|
|
Treasury shares, at cost; 958,481 and 156,737 shares in 2019 and 2018, respectively |
0
|
|
|
0
|
|
|
|
|
Accumulated other comprehensive income, net of tax |
|
|
|
0
|
|
|
|
|
Total equity |
(42,928)
|
|
|
(38,840)
|
|
|
|
|
Total liabilities, redeemable noncontrolling interest and stockholders’ equity |
30,529
|
|
|
26,312
|
|
|
|
|
Eliminations |
|
|
|
|
|
|
|
|
Current assets: |
|
|
|
|
|
|
|
|
Cash and cash equivalents |
0
|
|
|
0
|
|
|
|
|
Receivables: |
|
|
|
|
|
|
|
|
Trade, operating, net of allowance for doubtful accounts |
0
|
|
|
0
|
|
|
|
|
Trade, dry-leasing |
0
|
|
|
0
|
|
|
|
|
Tax receivables |
0
|
|
|
0
|
|
|
|
|
Other |
0
|
|
|
0
|
|
|
|
|
Inventories, net |
0
|
|
|
0
|
|
|
|
|
Prepaid expenses |
0
|
|
|
0
|
|
|
|
|
Total current assets |
0
|
|
|
0
|
|
|
|
|
Property and equipment |
0
|
|
|
0
|
|
|
|
|
Accumulated depreciation |
0
|
|
|
0
|
|
|
|
|
Property and equipment, net |
0
|
|
|
0
|
|
|
|
|
Operating lease right-of-use |
0
|
|
|
|
|
|
|
|
Equity investments and advances |
|
|
|
0
|
|
|
|
|
Investments in consolidated subsidiaries |
(181,684)
|
|
|
(172,950)
|
|
|
|
|
Intangible assets |
0
|
|
|
0
|
|
|
|
|
Deferred income taxes |
(10,602)
|
|
|
(9,904)
|
|
|
|
|
Intercompany receivables |
(317,247)
|
|
|
(366,541)
|
|
|
|
|
Other assets |
0
|
|
|
0
|
|
|
|
|
Total assets |
(509,533)
|
|
|
(549,395)
|
|
|
|
|
Current liabilities: |
|
|
|
|
|
|
|
|
Accounts payable and accrued expenses |
0
|
|
|
0
|
|
|
|
|
Accrued wages and benefits |
0
|
|
|
0
|
|
|
|
|
Accrued interest |
0
|
|
|
0
|
|
|
|
|
Accrued income taxes |
0
|
|
|
0
|
|
|
|
|
Accrued other taxes |
0
|
|
|
0
|
|
|
|
|
Accrued contingencies |
0
|
|
|
0
|
|
|
|
|
Current portion of long-term debt |
0
|
|
|
0
|
|
|
|
|
Other current liabilities |
0
|
|
|
0
|
|
|
|
|
Total current liabilities |
0
|
|
|
0
|
|
|
|
|
Long-term debt |
0
|
|
|
0
|
|
|
|
|
Deferred income taxes |
(10,602)
|
|
|
(9,903)
|
|
|
|
|
Intercompany payables |
(317,269)
|
|
|
(366,574)
|
|
|
|
|
Operating lease liabilities |
0
|
|
|
|
|
|
|
|
Other liabilities |
0
|
|
|
0
|
|
|
|
|
Total liabilities |
(327,871)
|
|
|
(376,477)
|
|
|
|
|
Redeemable noncontrolling interest |
0
|
|
|
0
|
|
|
|
|
Equity: |
|
|
|
|
|
|
|
|
Common stock, $0.01 par value, 60,000,000 shares authorized; 21,419,462 and 21,765,404 outstanding in 2019 and 2018, respectively, exclusive of treasury shares |
0
|
|
|
0
|
|
|
|
|
Additional paid-in capital |
(104,869)
|
|
|
(104,869)
|
|
|
|
|
Retained earnings |
(76,793)
|
|
|
(68,049)
|
|
|
|
|
Treasury shares, at cost; 958,481 and 156,737 shares in 2019 and 2018, respectively |
0
|
|
|
0
|
|
|
|
|
Accumulated other comprehensive income, net of tax |
|
|
|
0
|
|
|
|
|
Total equity |
(181,662)
|
|
|
(172,918)
|
|
|
|
|
Total liabilities, redeemable noncontrolling interest and stockholders’ equity |
$ (509,533)
|
|
|
$ (549,395)
|
|
|
|
|
|
|