Short-Term Borrowings (Short-Term Borrowings And The Related Weighted-Average Interest Rates) (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Short-term Debt [Line Items]
Short-term borrowings	$ 214,962	$ 254,766
Federal Funds Purchased [Member]
Short-term Debt [Line Items]
Weighted-Average Rate	0.20%	0.20%
Short-term borrowings	5,446	7,120	8,542
Securities Sold Under Agreements To Repurchase [Member]
Short-term Debt [Line Items]
Weighted-Average Rate	0.09%	0.07%
Short-term borrowings	$ 209,516	$ 247,646	$ 183,097