Profits Interest Awards - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Profit Interest Units [Line Items]
Profits interest compensation expense	$ 29,271	$ 19,517	$ 29,271	$ 19,517
Class B Shares [Member]
Profit Interest Units [Line Items]
Profits interest compensation expense			8,902	19,517
Incremental non cash compensation			$ 20,369