Debt And Shareholders' Equity (Schedule Of Changes In Accumulated Other Comprehensive Income (Loss)) (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Debt And Shareholders' Equity [Line Items]
Document Fiscal Year Focus			2013
Interest income expense, net, after tax	$ 55,385,000	$ 55,215,000	$ 143,709,000	$ 80,704,000
Income Tax Expense (Benefit)	43,091,000	51,036,000	103,725,000	102,895,000
Interest Income (Expense), Net	430,657,000	426,344,000	848,772,000	863,822,000
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net	4,217,000	7,308,000	14,334,000	17,517,000
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax			64,437,000	13,919,000
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax			7,164,000	2,018,000
Beginning balance			(446,157,000)	(592,084,000)
Other comprehensive income (loss)	32,347,000	(4,580,000)	71,601,000	15,937,000
Ending balance	(374,556,000)	(576,147,000)	(374,556,000)	(576,147,000)
Accumulated Net Unrealized Investment Gain (Loss) [Member]
Debt And Shareholders' Equity [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax			64,440,000	13,742,000
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax			8,590,000	7,151,000
Beginning balance			(397,616,000)	(546,763,000)
Other comprehensive income (loss)			73,030,000	20,893,000
Ending balance	(324,586,000)	(525,870,000)	(324,586,000)	(525,870,000)
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]
Debt And Shareholders' Equity [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax			(3,000)	177,000
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax			(1,426,000)	(5,133,000)
Beginning balance			1,794,000	9,404,000
Other comprehensive income (loss)			(1,429,000)	(4,956,000)
Ending balance	365,000	4,448,000	365,000	4,448,000
Accumulated Defined Benefit Plans Adjustment [Member]
Debt And Shareholders' Equity [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax			0	0
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax			0	0
Beginning balance			(50,335,000)	(54,725,000)
Other comprehensive income (loss)			0	0
Ending balance	(50,335,000)	(54,725,000)	(50,335,000)	(54,725,000)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Net Unrealized Investment Gain (Loss) [Member]
Debt And Shareholders' Equity [Line Items]
Gain (Loss) on Investments, Excluding Other than Temporary Impairments	(1,153,000)	5,519,000	2,146,000	6,239,000
Interest income expense, net, after tax	(2,549,000)	(4,302,000)	(8,548,000)	(10,606,000)
Income Tax Expense (Benefit)	(1,668,000)	(2,665,000)	(5,384,000)	(6,570,000)
Other than temporary impairment losses investments accretion of noncreidt portion held to maturity securities, after tax	(4,419,000)	(1,188,000)	(8,590,000)	(7,151,000)
Other than temporary impairment losses investments accretion of noncredit portion held to maturity securities, tax	(521,000)	247,000	(386,000)	349,000
Other than Temporary Impairment Losses, Investments, Accretion of Noncredit Portion, Held-to-maturity Securities, before Tax	(637,000)	(614,000)	(981,000)	(881,000)
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net	(4,217,000)	(6,967,000)	(13,932,000)	(17,176,000)
Interest Rate Contract [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]
Debt And Shareholders' Equity [Line Items]
Interest income expense, net, after tax	469,000	1,932,000	1,426,000	5,133,000
Income Tax Expense (Benefit)	308,000	1,267,000	956,000	3,360,000
Interest Income (Expense), Net	777,000	3,199,000	2,382,000	8,493,000
Fixed income securities gain loss [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Net Unrealized Investment Gain (Loss) [Member]
Debt And Shareholders' Equity [Line Items]
Interest income expense, net, after tax	(712,000)	3,481,000	1,325,000	3,987,000
Income Tax Expense (Benefit)	(441,000)	2,038,000	821,000	2,252,000
Long-term Debt [Member]
Debt And Shareholders' Equity [Line Items]
Debt Instrument, Face Amount 1	$ 49,000,000		$ 69,000,000