Summary of Gain or Loss Recognized and Amounts and Location of Income or Expense and Gain or Loss Reclassified into Income for Interest Rate Contracts and Foreign Currency Contracts (Detail) (Interest rate agreements, Interest Expense, USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Interest rate agreements | Interest Expense
Derivative [Line Items]
Interest rate agreements	$ 1,872	$ 1,925