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, 2017	Dec. 31, 2016	Dec. 31, 2015
Equity [Abstract]
Beginning balance		94,709,290	93,843,847	58,388,808
Issuance of class A common stock	25,875,000	12,421,401	1,070	34,780,622
Issuance of restricted class A common stock, net		922,196	836,867	651,815
Issuance of deferred stock units		28,190	27,506	22,602
Ending balance		108,081,077	94,709,290	93,843,847