v3.5.0.2
Condensed Consolidating Financial Information - Guarantor Subsidiaries - Condensed Consolidating Statements of Operations (Detail) - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2016
Jun. 30, 2015
Jun. 30, 2016
Jun. 30, 2015
Condensed Income Statements, Captions [Line Items]        
Operating revenues, net $ 167,136 $ 198,547 $ 331,152 $ 402,744
Expenses:        
Direct expenses 152,417 168,828 304,971 338,035
Selling, general and administrative expenses 11,778 12,047 23,451 23,284
Total operating expenses 164,195 180,875 328,422 361,319
Loss (gain) on disposal of assets, net (4,298) (66) (3,939) (73)
Equity in loss of unconsolidated affiliate 76 106 76 174
Operating income 7,163 17,632 6,593 41,324
Interest expense 7,540 7,155 15,073 14,325
Other income, net (494) (567) (1,109) (1,029)
Total expenses 7,046 6,588 13,964 13,296
Earnings (loss) before income taxes 117 11,044 (7,371) 28,028
Income tax (benefit) expense (4,160) 4,590 (2,716) 11,211
Net earnings (loss) 4,277 6,454 (4,655) 16,817
Parent Company Only (issuer) [Member]        
Condensed Income Statements, Captions [Line Items]        
Operating revenues, net 89,365 115,040 181,234 243,697
Expenses:        
Direct expenses 89,535 103,483 181,572 209,965
Selling, general and administrative expenses 9,232 9,471 18,275 17,979
Total operating expenses 98,767 112,954 199,847 227,944
Loss (gain) on disposal of assets, net (4,298) (66) (3,939) (73)
Equity in loss of unconsolidated affiliate 76 106 76 174
Operating income (5,180) 2,046 (14,750) 15,652
Equity in net income of consolidated subsidiaries (7,035) (9,230) (12,090) (15,362)
Interest expense 7,534 7,155 15,047 14,325
Other income, net (819) (571) (1,603) (1,034)
Total expenses (320) (2,646) 1,354 (2,071)
Earnings (loss) before income taxes (4,860) 4,692 (16,104) 17,723
Income tax (benefit) expense (9,137) (1,762) (11,449) 906
Net earnings (loss) 4,277 6,454 (4,655) 16,817
Guarantor Subsidiaries [Member]        
Condensed Income Statements, Captions [Line Items]        
Operating revenues, net [1] 77,771 83,507 149,918 159,047
Expenses:        
Direct expenses [1] 62,882 65,349 123,399 128,079
Selling, general and administrative expenses [1] 2,871 2,576 5,674 5,305
Total operating expenses [1] 65,753 67,925 129,073 133,384
Operating income [1] 12,018 15,582 20,845 25,663
Interest expense [1] 6   26  
Other income, net [1]     (4) (4)
Total expenses [1] 6   22 (4)
Earnings (loss) before income taxes [1] 12,012 15,582 20,823 25,667
Income tax (benefit) expense [1] 4,977 6,352 8,733 10,305
Net earnings (loss) [1] 7,035 9,230 12,090 15,362
Eliminations [Member]        
Expenses:        
Direct expenses   (4)   (9)
Selling, general and administrative expenses (325)   (498)  
Total operating expenses (325) (4) (498) (9)
Operating income 325 4 498 9
Equity in net income of consolidated subsidiaries 7,035 9,230 12,090 15,362
Other income, net 325 4 498 9
Total expenses 7,360 9,234 12,588 15,371
Earnings (loss) before income taxes (7,035) (9,230) (12,090) (15,362)
Net earnings (loss) $ (7,035) $ (9,230) $ (12,090) $ (15,362)
[1] Foreign subsidiaries represent minor subsidiaries and are included in the guarantor subsidiaries' amounts.