Borrowings (Other Short-Term Borrowings) (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012		Dec. 31, 2011
Securities sold under repurchase agreements	$ 306,257	[1]	$ 292,616	[1]
Federal funds purchased	456,000		318,000
Swap collateral	0		2,690
Total short-term borrowings	$ 762,257		$ 613,306

[1] Securities sold under agreement to repurchase are classified as secured short-term borrowings and are recorded at the amount of cash received in connection with the transaction. The securities underlying the repurchase agreements remain in available-for-sale investment securities.