Net Income (Loss) Per Share - Calculation of Basic and Diluted Weighted-Average Number of Shares of Common Stock and EPS (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Basic:
Net income (loss), basic	$ (68,851)	$ 27,512	$ (66,024)	$ 13,414
Net income (loss), shares, basic	35,856	35,678	35,816	30,645
Net income (loss), per shares, basic	$ (1.92)	$ 0.77	$ (1.84)	$ 0.44
Weighted-average number of shares of common stock-diluted:
Restricted stock and performance unit awards		148		185
Diluted:
Net income (loss), diluted	$ (68,851)	$ 27,512	$ (66,024)	$ 13,414
Net income (loss), shares, diluted	35,856	35,826	35,816	30,830
Net income (loss), per shares, diluted	$ (1.92)	$ 0.77	$ (1.84)	$ 0.44