Equity-Based Compensation - Activity of RDUs Available for Future Grants (Detail)	3 Months Ended
	Mar. 31, 2014
Activity of RDUs available for future grants
Restricted Depository Units Available For Future Grants Beginning Balance	1,652,309
Restricted Depository Units Available For Future Grants, Purchases	9,719
Restricted Depository Units Available For Future Grants Granted	(18,426)
Restricted Depository Units Available For Future Grants Forfeited	2,861
Restricted Depository Units Available For Future Grants, Ending Balance	1,646,463