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	3 Months Ended
	May 31, 2013	Mar. 31, 2019	Mar. 31, 2018
Equity [Abstract]
Beginning balance		123,664,577	108,081,077
Issuance of class A common stock	25,875,000	1,909,909	455
Issuance of restricted class A common stock, net		320,903	309,775
Issuance of deferred stock units		7,964	7,871
Ending balance		125,903,353	108,399,178