Rent Expense (Detail) (USD $) In Thousands, unless otherwise specified	7 Months Ended	12 Months Ended
	Dec. 31, 2010	Dec. 31, 2012	Dec. 31, 2011	May 31, 2010
Schedule of Rent Expense [Line Items]
Rent expense	$ 11,003	$ 18,493	$ 20,223	$ 10,328