Securities Sold Under Agreements To Repurchase And Other Borrowings (Summary Of Securities Sold Under Agreements To Repurchase And Other Borrowings) (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Securities Sold Under Agreements to Repurchase and Other Short-term Borrowings [Line Items]
Securities sold under agreements to repurchase	$ 987,290	$ 1,076,160
Federal funds purchased	385,000	0
Total securities sold under agreements to repurchase and other borrowings	1,372,290	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	337,290	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	100,000	300,000
Non-Callable [Member]
Securities Sold Under Agreements to Repurchase and Other Short-term Borrowings [Line Items]
Securities sold under agreements to repurchase	$ 550,000	$ 450,000