Equity - Schedule of Movement in Outstanding Shares of Class A Common Stock, Restricted Class A Common Stock and Deferred Stock Units (Detail)	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Equity [Abstract]
Beginning balance	29,602,884	3,016,407
Issuance of class A common stock	28,175,003	25,875,000
Issuance of deferred stock units	15,104	6,758
Ending balance	57,792,991	28,898,165