Shareholders' Equity And Other Comprehensive Income (Summary Of Tax Effects Of Each Component Of Other Comprehensive Income) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Oct. 31, 2011
Shareholders' Equity And Other Comprehensive Income [Abstract]
Unrealized holding gains (losses) arising during the period, Before-Tax Amount	$ (1,056)	$ 2,882
Unrealized holding gains (losses) arising during the period, Tax (Expense) Benefit	370	(1,009)
Unrealized holding gains (losses) arising during the period, Net-of-Tax Amount	(686)	1,873
Other-than-temporary impairment realized in net income, Before-Tax Amount
Other-than-temporary impairment realized in net income, Tax (Expense) Benefit
Other-than-temporary impairment realized in net income, Net-of-Tax Amount
Less: reclassification adjustment for (gains) included in net income, Before-Tax Amount	(2,800)	(1)
Less: reclassification adjustment for (gains) included in net income, Tax (Expense) Benefit	980
Less: reclassification adjustment for (gains) included in net income, Net-of-Tax Amount	(1,820)	(1)
Net unrealized gains (losses), Before-Tax Amount	(3,856)	2,881
Net unrealized gains (losses), Tax (Expense) Benefit	1,350	(1,009)
Net unrealized gains (losses), Net-of-Tax Amount	(2,506)	1,872
Change in fair value of derivative instruments designated as cash flow hedges during the period, Before-Tax Amount	4,951	1,095
Change in fair value of derivative instruments designated as cash flow hedges during the period, Tax (Expense) Benefit	(1,733)	(383)
Change in fair value of derivative instruments designated as cash flow hedges during the period, Net-of-Tax Amount	3,218	712
Less: reclassification adjustment for losses (gains) included in net income, Before-Tax Amount	386	427
Less: reclassification adjustment for losses (gains) included in net income, Tax (Expense) Benefit	(135)	(150)
Less: reclassification adjustment for losses (gains) included in net income, Net-of-Tax Amount	251	277
Fair value of derivative instruments designated as cash flow hedges, Before-Tax Amount	5,337	1,522
Fair value of derivative instruments designated as cash flow hedges, Tax (Expense) Benefit	(1,868)	(533)
Fair value of derivative instruments designated as cash flow hedges, Net-of-Tax Amount	3,469	989
Total other comprehensive income, Before-Tax Amount	1,481	4,403
Total other comprehensive income, Tax (Expense) Benefit	(518)	(1,542)
Total other comprehensive income, Net-of-Tax Amount	$ 963	$ 2,861
Number of shares authorized to repurchase			900,000