Fair Value Measurement - Reconciliation of All Assets Measured at Fair Value on Recurring Basis Using Significant Unobservable Inputs (Level 3) (Detail) (Interest Rate Cap [Member], USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Interest Rate Cap [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance of recurring Level 3 assets at beginning of period	$ 436	$ 1,933
Included in other income	547	(1,077)
Included in other comprehensive income
Purchases
Amortization	(389)	(346)
Sales
Balance of recurring Level 3 assets at end of period	$ 594	$ 510