Summary of Significant Accounting Policies - Reconciliation of Basic and Diluted Income (Loss) Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Earnings Per Share Basic And Diluted [Abstract]
Net income (loss)	$ 7,360	$ (12,217)	$ (16,279)	$ 1,424	$ 6,913	$ 2,215	$ 4,840	$ (1,807)	$ (19,712)	$ 12,161	$ 175,698
Denominator:
Weighted average common shares outstanding, basic									85,107,301	89,115,997	90,272,257
Basic earnings per share:
Net income (loss) per share	$ 0.09	$ (0.14)	$ (0.19)	$ 0.02	$ 0.08	$ 0.02	$ 0.05	$ (0.02)	$ (0.23)	$ 0.14	$ 1.95
Denominator:
Weighted average common shares outstanding, basic									85,107,301	89,115,997	90,272,257
Dilutive securities:
Stock options										629,933	906,519
Restricted stock units										582,653	713,181
Weighted average common shares outstanding, diluted									85,107,301	90,328,583	91,891,957
Diluted earnings per share:
Net income (loss) per share	$ 0.09	$ (0.14)	$ (0.19)	$ 0.02	$ 0.08	$ 0.02	$ 0.05	$ (0.02)	$ (0.23)	$ 0.13	$ 1.91