Other Comprehensive Income (Loss) (Component Of Other Comprehensive Income (Loss)) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Other Comprehensive Income (Loss) [Abstract]
Securities available for sale, Change in net unrealized gain/loss during the period, Before Tax Amount	$ 1,882	$ 8,290
Securities available for sale, Change in net unrealized gain/loss during the period, Tax Expense (Benefit)	658	2,902
Securities available for sale, Change in net unrealized gain/loss during the period, Net of Tax Amount	1,224	5,388
Securities available for sale, Reclassification adjustment for (gains) losses included in net income, Before Tax Amount	491	(5)
Securities available for sale, Reclassification adjustment for net (gains) losses included in net income, Tax Expense (Benefit)	172	(2)
Securities available for sale, Reclassification adjustment for net (gains) losses included in net income, Net of Tax Amount	319	(3)
Total securities available for sale, Before Tax Amount	2,373	8,285
Total securities available for sale, Tax Expense (Benefit)	830	2,900
Total securities available for sale, Net of Tax Amount	1,543	5,385
Defined-benefit post-retirement benefit plans, Change in the net actuarial gain/loss, Before Tax Amount	1,229	783
Defined-benefit post-retirement benefit plans, Change in the net actuarial gain/loss, Tax Expense (Benefit)	430	274
Defined-benefit post-retirement benefit plans, Change in the net actuarial gain/loss, Net of Tax Amount	799	509
Derivatives, Change in the accumulated gain/loss on effective cash flow hedge derivatives, Before Tax Amount	(427)	65
Derivatives, Change in the accumulated gain/loss on effective cash flow hedge derivatives, Tax Expense (Benefit)	(150)	23
Derivatives, Change in the accumulated gain/loss on effective cash flow hedge derivatives, Net of Tax Amount	(277)	42
Reclassification adjustments for (gains) losses included in net income, Interest rate swaps on variable-rate loans, Before Tax Amount	(9,345)	(9,345)
Reclassification adjustments for (gains) losses included in net income, Interest rate swaps on variable-rate loans, Tax Expense (Benefit)	(3,271)	(3,271)
Reclassification adjustments for (gains) losses included in net income, Interest rate swaps on variable-rate loans, Net of Tax Amount	(6,074)	(6,074)
Reclassification adjustments for (gains) losses included in net income, Interest rate swap on junior subordinated deferrable interest debentures, Before Tax Amount	1,033	1,086
Reclassification adjustments for (gains) losses included in net income, Interest rate swap on junior subordinated deferrable interest debentures, Tax Expense (Benefit)	362	380
Reclassification adjustments for (gains) losses included in net income, Interest rate swap on junior subordinated deferrable interest debentures, Net of Tax Amount	671	706
Total derivatives, Before Tax Amount	(8,739)	(8,194)
Total derivatives, Tax Expense (Benefit)	(3,059)	(2,868)
Total derivatives, Net of Tax Amount	(5,680)	(5,326)
Total other comprehensive income, Before Tax Amount	(5,137)	874
Total other comprehensive income, Tax Expense (Benefit)	(1,799)	306
Total other comprehensive income, Net of Tax Amount	$ (3,338)	$ 568