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, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Numerator:
Net income (loss) attributable to common stockholders	$ 20,328	$ 9,016	$ 2,338	$ (35,592)	$ 7,360	$ (12,217)	$ (16,279)	$ 1,424	$ (3,910)	$ (19,712)	$ 12,161
Denominator:
Weighted average common shares outstanding, basic									84,231,212	85,107,301	89,115,997
Basic earnings per share:
Net income (loss) per share attributable to common stockholders									$ (0.05)	$ (0.23)	$ 0.14
Numerator:
Net income (loss) attributable to common stockholders	$ 20,328	$ 9,016	$ 2,338	$ (35,592)	$ 7,360	$ (12,217)	$ (16,279)	$ 1,424	$ (3,910)	$ (19,712)	$ 12,161
Denominator:
Weighted average common shares outstanding, basic									84,231,212	85,107,301	89,115,997
Dilutive securities:
Stock options											629,933
Restricted stock units											582,653
Weighted average common shares outstanding, diluted									84,231,212	85,107,301	90,328,583
Diluted earnings per share:
Net income (loss) per share attributable to common stockholders									$ (0.05)	$ (0.23)	$ 0.13