Equity - Schedule of Movement in Outstanding Shares of Class A Common Stock, Restricted Class A Common Stock and Deferred Stock Units (Detail)	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Equity [Abstract]
Beginning balance	29,602,884	3,016,405
Issuance of class A common stock	19,130,868	25,875,000
Issuance of deferred stock units	10,009	3,070
Vesting of restricted class A common stock	(155,867)
Ending balance	48,587,894	28,894,475