Securities Sold Under Agreements To Repurchase And Other Short-Term Borrowings (Repurchase Agreements Outstanding) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011 months	Dec. 31, 2010
Assets Sold under Agreements to Repurchase [Line Items]
Balance	$ 941,706	$ 839,144
Fair Value of Collateral	1,041,925
Weighted-Average Rate	1.65%
Weighted-Average Current Maturity	39.92
Up To 30 Days [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Balance	280,599
Fair Value of Collateral	287,347
Weighted-Average Rate	0.20%
Weighted-Average Current Maturity	3.12
31 To 90 Days [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Balance	5,605
Fair Value of Collateral	5,873
Weighted-Average Rate	0.22%
Weighted-Average Current Maturity	1.94
Over 90 Days [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Balance	655,502
Fair Value of Collateral	$ 748,705
Weighted-Average Rate	2.24%
Weighted-Average Current Maturity	57.92