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		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Basic:
Net income (loss), basic	$ (92,200)	$ 4,284	$ (158,227)	$ 17,698
Net income (loss), shares, basic	36,035	35,684	35,889	32,343
Net income (loss), per shares, basic	$ (2.56)	$ 0.12	$ (4.41)	$ 0.55
Weighted-average number of shares of common stock-diluted:
Restricted stock and performance unit awards		13		128
Diluted:
Net income (loss), diluted	$ (92,200)	$ 4,284	$ (158,227)	$ 17,698
Net income (loss), shares, diluted	36,035	35,697	35,889	32,471
Net income (loss), per shares, diluted	$ (2.56)	$ 0.12	$ (4.41)	$ 0.55