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, 2015	Jun. 30, 2015	Jun. 30, 2014
Equity [Abstract]
Beginning balance		58,388,808	29,602,884
Issuance of class A common stock	280,025	34,780,298	18,975,001
Issuance of restricted class A common stock, net		179,799
Issuance of deferred stock units		10,665	10,009
Ending balance		93,359,570	48,587,894