Securities Sold Under Agreements To Repurchase And Other Short-Term Borrowings (Summary Of Securities Sold Under Agreements To Repurchase And Other Short-Term Borrowings) (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Securities Sold Under Agreements to Repurchase and Other Short-term Borrowings [Line Items]
Securities sold under agreements to repurchase	$ 970,349	$ 1,076,160
Federal funds purchased	243,000	0
Total securities sold under agreements to repurchase and other borrowings	1,213,349	1,076,160
Original Maturity Of One Year Or Less [Member]
Securities Sold Under Agreements to Repurchase and Other Short-term Borrowings [Line Items]
Securities sold under agreements to repurchase	320,349	326,160
Callable At The Option Of The Counterparty [Member]
Securities Sold Under Agreements to Repurchase and Other Short-term Borrowings [Line Items]
Securities sold under agreements to repurchase	200,000	300,000
Non-Callable [Member]
Securities Sold Under Agreements to Repurchase and Other Short-term Borrowings [Line Items]
Securities sold under agreements to repurchase	$ 450,000	$ 450,000