Income Taxes (Reconciliation Of Income Taxes) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Federal statutory rate	35.00%
Computed tax expense	$ 85,785	$ 63,837	$ 200,039
Tax-exempt interest income	(31,414)	(33,966)	(34,210)
Dividends received deduction	(1,704)	(1,463)	(1,689)
State tax expense (benefit)	1,299	(3,580)	3,688
Other, net	(31)	5,364	641
Total	53,935	30,192	168,469
Parent Company [Member]
Total	$ (684)	$ (3,507)	$ 4,400