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								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Earnings Per Share [Abstract]
Net income	$ 78,931	$ 74,897	$ 75,174	$ 76,565	$ 73,643	$ 78,165	$ 72,312	$ 60,958	$ 305,567	$ 285,078	$ 217,631
Weighted-average shares outstanding, basic and diluted									130,085,398	113,857,238	95,963,616
Per share amount, basic and diluted	$ 0.59	$ 0.56	$ 0.59	$ 0.62	$ 0.61	$ 0.67	$ 0.66	$ 0.56	$ 2.35	$ 2.50	$ 2.27