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
	Mar. 31, 2017	Mar. 31, 2016
Earnings Per Share [Abstract]
Net income	$ 51,405	$ 57,047
Weighted-average shares outstanding, basic and diluted	94,993,386	94,067,769
Per share amount, basic and diluted	$ 0.54	$ 0.61