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, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Earnings Per Share [Abstract]
Net income	$ 75,174	$ 72,312	$ 151,738	$ 133,271
Weighted-average shares outstanding, basic and diluted	126,475,244	109,069,078	125,410,064	108,735,193
Per share amount, basic and diluted	$ 0.59	$ 0.66	$ 1.21	$ 1.23