Equity - Schedule of Movement in Outstanding Shares of Class A Common Stock, Restricted Class A Common Stock and Deferred Stock Units (Detail) - shares	1 Months Ended	12 Months Ended
	May 31, 2013	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Equity [Abstract]
Beginning balance		108,081,077	94,709,290	93,843,847
Issuance of class A common stock	25,875,000	14,568,431	12,421,401	1,070
Issuance of restricted class A common stock, net		983,447	922,196	836,867
Issuance of deferred stock units		31,622	28,190	27,506
Ending balance		123,664,577	108,081,077	94,709,290