Other Comprehensive Income (Loss) (Other Comprehensive Income (Loss) Components And Related Taxes) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Other Comprehensive Income (Loss) [Abstract]
Unrealized gains on available-for-sale securities, Before-tax amount	$ 12,085	$ 6,934	$ 8,919	$ 12,479
Unrealized gains on available-for-sale securities, Tax expense (benefit)	4,229	2,428	3,121	4,368
Unrealized gains on available-for-sale securities, Net-of-tax amount	7,856	4,506	5,798	8,111
Reclassification adjustment for gains realized in net income, Before-tax amount	(15,362)	(3,515)	(21,997)	(11,819)
Reclassification adjustment for gains realized in net income, Tax expense (benefit)	(5,377)	(1,231)	(7,699)	(4,137)
Reclassification adjustment for gains realized in net income, Net-of-tax amount	(9,985)	(2,284)	(14,298)	(7,682)
Unrealized net holding gain (loss) on cash flow hedge, Before-tax amount	93	(153)	297	(324)
Unrealized net holding gain (loss) on cash flow hedge, Tax expense (benefit)	33	(53)	104	(113)
Unrealized net holding gain (loss) on cash flow hedge, Net-of-tax amount	60	(100)	193	(211)
Other comprehensive loss, Before-tax amount	(3,184)	3,266	(12,781)	336
Other comprehensive loss, Tax expense (benefit)	(1,115)	1,144	(4,474)	118
Other comprehensive loss, Net-of-tax amount	$ (2,069)	$ 2,122	$ (8,307)	$ 218