Income Taxes (Effective Income Tax Reconciliation) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Tax Disclosure [Abstract]
U.S. federal income tax rate									35.00%
Income Tax Expense (Benefit) Reconciliation
Taxes at statutory federal income tax rate									$ 88,420	$ 11,017	$ (20,836)
State income tax benefit, net of federal income tax benefit, before valuation allowance									9,877	(3,935)	(3,084)
Tax-exempt income									(1,407)	(2,026)	(2,316)
Tax credits									(1,473)	(1,558)	(1,461)
Cash surrender value of life insurance									(2,932)	(2,907)	(2,911)
Change in valuation allowance, federal and state	(796,300)								(4,083)	(802,771)	31,844
Other, net									4,842	3,448	76
Total income tax expense (benefit) expense	$ 21,130	$ 27,765	$ 27,371	$ 16,979	$ (796,339)	$ (211)	$ (2,105)	$ (77)	$ 93,245	$ (798,732)	$ 1,312