Quarterly Results of Operations (Unaudited) - Schedule of Quarterly Results of Operations (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Revenues	$ 106,091	$ 123,640	$ 142,439	$ 166,561	$ 201,630	$ 201,402	$ 215,276	$ 226,002	$ 538,731	$ 844,310	$ 930,957
Cost of sales	77,794	77,633	79,881	93,096	108,352	108,132	117,664	125,138	328,404	459,286	513,527
Gross profit	28,297	46,007	62,558	73,465	93,278	93,270	97,612	100,864
Operating income (loss)	(4,634)	22,933	45,217	49,343	60,308	64,255	52,579	71,693	112,859	248,835	278,748
Net income	$ 1,302	$ 19,013	$ 36,137	$ 36,769	$ 48,354	$ 50,777	$ 39,213	$ 53,664	$ 93,221	$ 192,008	$ 208,712
Basic (in dollars per share)	$ 0.03	$ 0.51	$ 0.96	$ 0.97	$ 1.28	$ 1.32	$ 1.01	$ 1.38	$ 2.48	$ 5.00	$ 5.22
Diluted (in dollars per share)	$ 0.03	$ 0.51	$ 0.96	$ 0.97	$ 1.28	$ 1.32	$ 1.01	$ 1.38	$ 2.47	$ 4.98	$ 5.19