Other Comprehensive Income (Loss) (Other Comprehensive Income (Loss) Components And Related Taxes) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Other Comprehensive Income (Loss) [Abstract]
Unrealized gains (losses) on available-for-sale securities, Before-tax amount	$ 17,532	$ (5,321)	$ 26,451	$ 7,158
Unrealized gains (losses) on available-for-sale securities, Tax expense (benefit)	6,136	(1,862)	9,257	2,506
Unrealized gains (losses) on available-for-sale securities, Net-of-tax amount	11,396	(3,459)	17,194	4,652
Reclassification adjustment for gains realized in net income, Before-tax amount	(3,465)		(25,462)	(11,819)
Reclassification adjustment for gains realized in net income, Tax expense (benefit)	(1,213)		(8,912)	(4,137)
Reclassification adjustment for gains realized in net income, Net-of-tax amount	(2,252)		(16,550)	(7,682)
Unrealized net holding gain (loss) on cash flow hedge, Before-tax amount	238	(102)	535	(426)
Unrealized net holding gain (loss) on cash flow hedge, Tax expense (benefit)	83	(36)	187	(149)
Unrealized net holding gain (loss) on cash flow hedge, Net-of-tax amount	155	(66)	348	(277)
Other comprehensive income (loss), Before-tax amount	14,305	(5,423)	1,524	(5,087)
Other comprehensive income (loss), Tax expense (benefit)	5,006	(1,898)	532	(1,780)
Other comprehensive income (loss), Net-of-tax amount	9,299	(3,525)	992	(3,307)
Total comprehensive income	$ 29,700	$ 16,100	$ 72,522	$ 58,200