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	6 Months Ended
	May 31, 2013	Jun. 30, 2019	Jun. 30, 2018
Equity [Abstract]
Beginning balance		123,664,577	108,081,077
Issuance of class A common stock	25,875,000	10,535,181	3,252,325
Issuance of restricted class A common stock, net		317,339	305,703
Issuance of deferred stock units		15,697	15,919
Ending balance		134,532,794	111,655,024