Gains (Losses) Related to Interest Rate Derivatives Designated as Hedges of Cash Flows (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Amount of loss reclassified from accumulated other comprehensive loss to interest on short-term borrowings	$ (1,788)	$ (608)	$ (4,578)	$ (1,796)
Amount of loss recognized in other comprehensive (loss) income	$ (2,101)	$ (15,829)	$ (5,840)	$ (20,928)