Condensed Consolidating Financial Information - Guarantor Subsidiaries - Condensed Consolidating Statements of Operations (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Condensed Income Statements, Captions [Line Items]
Operating revenues, net	$ 148,336	$ 150,167	$ 146,424	$ 134,618	$ 144,853	$ 158,093	$ 167,136	$ 164,016	$ 579,545	$ 634,098	$ 804,228
Expenses:
Direct expenses									546,699	592,550	687,050
Selling, general, and administrative expenses									53,817	44,418	46,422
Total operating expenses									600,516	636,968	733,472
Loss (gain) on disposition of assets, net	(287)	(4)	(7)	0	504	85	(4,298)	359	298	(3,350)	339
Impairment of assets									368	407	0
Equity in profit (loss) of unconsolidated affiliate									385	(151)	306
Operating (loss) income									(22,022)	224	70,111
Interest expense									32,183	30,644	29,066
Other income, net									(2,764)	(3,271)	(2,211)
Total expenses									29,419	27,373	26,855
(Loss) earnings before income taxes	(20,319)	(4,899)	(3,150)	(23,073)	(12,012)	(7,766)	117	(7,488)	(51,441)	(27,149)	43,256
Income tax (benefit) expense									(58,973)	(469)	16,332
Net earnings (loss)	$ 29,330	$ (3,277)	$ (3,273)	$ (15,248)	$ (17,058)	$ (4,967)	$ 4,277	$ (8,932)	7,532	(26,680)	26,924
Parent Company Only (issuer) [Member]
Condensed Income Statements, Captions [Line Items]
Operating revenues, net									310,449	339,829	476,969
Expenses:
Direct expenses									326,152	347,532	426,239
Selling, general, and administrative expenses									41,134	32,911	35,694
Total operating expenses									367,286	380,443	461,933
Loss (gain) on disposition of assets, net									300	(3,350)	339
Impairment of assets									368	407
Equity in profit (loss) of unconsolidated affiliate									1,021	(151)	306
Operating (loss) income									(58,526)	(37,520)	14,391
Equity in net earnings of consolidated subsidiaries									(38,553)	(22,182)	(31,225)
Interest expense									32,161	30,585	28,946
Other income, net									(2,757)	(3,284)	(2,222)
Total expenses									(9,149)	5,119	(4,501)
(Loss) earnings before income taxes									(49,377)	(42,639)	18,892
Income tax (benefit) expense									(56,909)	(15,959)	(8,032)
Net earnings (loss)									7,532	(26,680)	26,924
Guarantor Subsidiaries [Member]
Condensed Income Statements, Captions [Line Items]
Operating revenues, net									262,229	293,329	327,259
Expenses:
Direct expenses									212,691	237,635	259,198
Selling, general, and administrative expenses									12,462	10,984	10,577
Total operating expenses									225,153	248,619	269,775
Loss (gain) on disposition of assets, net									(2)
Operating (loss) income									37,078	44,710	57,484
Interest expense									22	46	120
Other income, net									(2)	(5)	(7)
Total expenses									20	41	113
(Loss) earnings before income taxes									37,058	44,669	57,371
Income tax (benefit) expense									(1,138)	15,490	24,364
Net earnings (loss)									38,196	29,179	33,007
Non-Guarantor Subsidiaries [Member]
Condensed Income Statements, Captions [Line Items]
Operating revenues, net									23,871	940
Expenses:
Direct expenses									24,860	7,383	1,631
Selling, general, and administrative expenses									221	541	151
Total operating expenses									25,081	7,924	1,782
Equity in profit (loss) of unconsolidated affiliate									(636)
Operating (loss) income									(574)	(6,984)	(1,782)
Interest expense										13
Other income, net									(5)
Total expenses									(5)	13	0
(Loss) earnings before income taxes									(569)	(6,997)	(1,782)
Income tax (benefit) expense									(926)
Net earnings (loss)									357	(6,997)	(1,782)
Eliminations [Member]
Condensed Income Statements, Captions [Line Items]
Operating revenues, net									(17,004)
Expenses:
Direct expenses									(17,004)		(18)
Selling, general, and administrative expenses										(18)
Total operating expenses									(17,004)	(18)	(18)
Operating (loss) income									0	18	18
Equity in net earnings of consolidated subsidiaries									38,553	22,182	31,225
Other income, net									0	18	18
Total expenses									38,553	22,200	31,243
(Loss) earnings before income taxes									(38,553)	(22,182)	(31,225)
Net earnings (loss)									$ (38,553)	$ (22,182)	$ (31,225)