Derivative Financial Instruments - Information about Fair Values of Derivative Instruments in Consolidated Statement of Income (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives not designated as hedging instruments, Derivatives	$ 1,916	$ 851	$ 3,505	$ 925
Interest rate contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives not designated as hedging instruments, Derivatives	2,778	777	5,974	3,996
Foreign exchange and other option and futures contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives not designated as hedging instruments, Derivatives	(862)	74	(2,469)	(3,071)
Interest rate swap agreements [Member] | Fixed rate long-term borrowings [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives in fair value hedging relationships, Derivatives	(86)	3,273	(29,097)	5,918
Derivatives in fair value hedging relationships, Hedged item	$ (20)	$ (3,252)	$ 27,733	$ (5,876)