Earnings Per Share - Computation of Basic and Diluted Earnings Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Numerator:
Net income	$ 56,528	$ 26,262	$ 88,411	$ 26,333
Denominator:
Basic weighted-average shares outstanding (shares)	130,292,563	142,244,166	132,326,856	142,055,766
Effect of dilutive shares:
Stock options and unvested restricted stock units (shares)	214,004	227,025	436,919	375,959
Diluted weighted-average shares outstanding (shares)	130,506,567	142,471,191	132,763,775	142,431,725
Earnings per share
Basic (in dollars per share)	$ 0.43	$ 0.18	$ 0.67	$ 0.19
Diluted (in dollars per share)	$ 0.43	$ 0.18	$ 0.67	$ 0.18
Antidilutive stock options and unvested restricted stock units not included in diluted earnings per share (shares)	3,090,298	2,920,708	2,992,479	3,144,445