Prior Periods Financial Statement Revision - Schedule of Correction of Misstatements and Revision on Consolidated Statements of Operations (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Accounting Changes And Error Corrections [Line Items]
Cost of sales (exclusive of depreciation and amortization shown separately below)	$ 156,408	$ 111,272	$ 431,492	$ 340,266
Selling, general and administrative expense	22,480	16,985	71,298	51,630
Depreciation and amortization	21,259	13,384	51,798	39,006
Other operating income	733	0	638	270
Income (loss) from operations	5,881	5,551	9,283	32,045
Other (income) expense, net	(308)	755	(1,882)	1,192
Loss from continuing operations before benefit for income taxes and share of net income from joint venture	(19,659)	(6,406)	(58,753)	(46,304)
Benefit for income taxes	5,609	1,724	12,732	14,204
Loss from continuing operations	(13,784)	(3,480)	(44,277)	(27,961)
Income from discontinued operations, net of tax (Note 2)	0	129,441	0	140,195
Net income (loss)	(13,784)	125,961	(44,277)	112,234
Other comprehensive loss:
Foreign currency translation gain	(4,193)	6,411	(14,509)	21,027
Other comprehensive income	(4,193)	(2,832)	(14,509)	11,784
Comprehensive income (loss)	$ (17,977)	$ 123,129	$ (58,786)	$ 124,018
Basic net loss per share	$ (0.48)	$ 4.57	$ (1.59)	$ 4.10
Diluted net loss per share	$ (0.48)	$ 4.57	$ (1.59)	$ 4.10
As Previously Reported
Accounting Changes And Error Corrections [Line Items]
Cost of sales (exclusive of depreciation and amortization shown separately below)		$ 110,836		$ 339,345
Selling, general and administrative expense				52,606
Depreciation and amortization		13,075		38,432
Other operating income				0
Income (loss) from operations		6,296		32,294
Other (income) expense, net		(848)		(945)
Loss from continuing operations before benefit for income taxes and share of net income from joint venture		(5,568)		(46,302)
Benefit for income taxes		1,436		14,145
Loss from continuing operations		(2,930)		(28,018)
Income from discontinued operations, net of tax (Note 2)		135,825		146,579
Net income (loss)		132,895		118,561
Other comprehensive loss:
Foreign currency translation gain		6,083		20,327
Other comprehensive income		(3,160)		11,084
Comprehensive income (loss)		$ 129,735		$ 129,645
Basic net loss per share		$ 4.82		$ 4.33
Diluted net loss per share		$ 4.82		$ 4.33
Adjustment
Accounting Changes And Error Corrections [Line Items]
Cost of sales (exclusive of depreciation and amortization shown separately below)		$ 436		$ 921
Selling, general and administrative expense				(976)
Depreciation and amortization		309		574
Other operating income				(270)
Income (loss) from operations		(745)		(249)
Other (income) expense, net		93		(247)
Loss from continuing operations before benefit for income taxes and share of net income from joint venture		(838)		(2)
Benefit for income taxes		288		59
Loss from continuing operations		(550)		57
Income from discontinued operations, net of tax (Note 2)		(6,384)		(6,384)
Net income (loss)		(6,934)		(6,327)
Other comprehensive loss:
Foreign currency translation gain		328		700
Other comprehensive income		328		700
Comprehensive income (loss)		$ (6,606)		$ (5,627)
Basic net loss per share		$ (0.25)		$ (0.23)
Diluted net loss per share		$ (0.25)		$ (0.23)
Continuing Operations As Revised
Accounting Changes And Error Corrections [Line Items]
Cost of sales (exclusive of depreciation and amortization shown separately below)		$ 111,272		$ 340,266
Selling, general and administrative expense				51,630
Depreciation and amortization		13,384		39,006
Other operating income				(270)
Income (loss) from operations		5,551		32,045
Other (income) expense, net		(755)		(1,192)
Loss from continuing operations before benefit for income taxes and share of net income from joint venture		(6,406)		(46,304)
Benefit for income taxes		1,724		14,204
Loss from continuing operations		(3,480)		(27,961)
Income from discontinued operations, net of tax (Note 2)		129,441		140,195
Net income (loss)		125,961		112,234
Other comprehensive loss:
Foreign currency translation gain		6,411		21,027
Other comprehensive income		(2,832)		11,784
Comprehensive income (loss)		$ 123,129		$ 124,018
Basic net loss per share		$ 4.57		$ 4.10
Diluted net loss per share		$ 4.57		$ 4.10