Net Income Per Share - Summary of Table Reconciling Basic and Diluted Net Income Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018
Earnings Per Share [Abstract]
Net income	$ 62,964	$ 56,276	$ 44,001	$ 47,983	$ 119,240	$ 91,984
Basic Net Income Per Share, Weighted average common shares outstanding	172,985		151,878		173,855	151,800
Basic Net Income Per Share	$ 0.37		$ 0.29		$ 0.69	$ 0.61
Effect of dilutive securities: Restricted stock	643		623		626	610
Effect of dilutive securities: Stock options	47		67		50	73
Diluted Net Income Per Share, Weighted average shares outstanding	173,675		152,568		174,531	152,483
Diluted Net Income Per Share	$ 0.36		$ 0.29		$ 0.68	$ 0.60