Equity - Schedule of Basic and Diluted Earnings Per Share, or EPS, Based on Weighted-Average of Both Restricted and Unrestricted Class A Common Stock Outstanding (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Earnings Per Share [Abstract]
Net income	$ 50,613	$ 63,081	$ 102,018	$ 120,128
Weighted-average shares outstanding, basic and diluted	95,005,873	94,064,423	94,999,664	94,066,096
Per share amount, basic and diluted	$ 0.53	$ 0.67	$ 1.07	$ 1.28