Quarterly Results of Operations (Unaudited) (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Quarterly Financial Information Disclosure [Abstract]
Revenues	$ 97,335	$ 93,257	$ 94,861	$ 99,173	$ 107,973	$ 100,346	$ 127,922	$ 119,228	$ 384,626	$ 455,469	$ 538,731
Cost of sales	68,675	65,630	69,444	67,750	72,355	63,050	87,549	82,440	271,499	305,394	328,404
Gross profit	28,660	27,627	25,417	31,423	35,618	37,296	40,373	36,788
Operating income (loss)	(98,826)	(14,084)	(3,551)	(6,277)	(5,107)	(62,045)	(1,114)	(870)	(122,738)	(69,136)	112,859
Net income (loss)	$ (74,912)	$ (10,358)	$ (3,042)	$ (7,383)	$ (71,488)	$ (29,260)	$ 15	$ 94	$ (95,695)	$ (100,639)	$ 93,221
Earnings (loss) per share:
Basic (in dollars per share)	$ (2.09)	$ (0.28)	$ (0.08)	$ (0.20)	$ 0.03	$ (0.78)	$ 0.00	$ 0.00	$ (2.58)	$ (2.69)	$ 2.48
Diluted (in dollars per share)	$ (2.09)	$ (0.28)	$ (0.08)	$ (0.20)	$ 0.03	$ (0.78)	$ 0.00	$ 0.00	$ (2.58)	$ (2.69)	$ 2.47