Consolidated Statements Of Comprehensive Income (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Consolidated Statements Of Comprehensive Income [Abstract]
Net income	$ 101,891	$ 74,496	$ 28,326
Available for sale securities:
Unrealized (losses) gains arising during the period	(12,004)	22,101	1,305
Reclassification adjustment for net gains realized in earnings (net of tax expense $1,609, $3,094, and $930 in 2012, 2011, and 2010, respectively)	(2,414)	(4,641)	(1,396)
Income tax benefit (expense) related to unrealized gains (losses)	4,802	(8,840)	(522)
Net change in unrealized gains	(9,616)	8,620	(613)
Held to maturity securities:
Unrealized (losses) gain related to factors other than credit (net of tax expense of $34 in 2011 and tax benefit of $150 in 2010)		(52)	225
Reclassification adjustment for impairments realized in net income (net of tax benefit of $42, $108, and $137 in 2012, 2011, and 2010, respectively)	62	161	205
Accretion of unrealized losses related to factors other than credit to investment securities held to maturity (net of tax benefit of $84, $66, and $115 in 2012 2011, and 2010, respectively)	126	100	173
Net change in unrealized losses related to factors other than credit	188	209	603
Other comprehensive (loss) income, net of tax	(9,428)	8,829	(10)
Comprehensive income	$ 92,463	$ 83,325	$ 28,316