Investments (Schedule Of Available-For-Sale Securities) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Amortized Cost	$ 1,140,422	$ 1,288,113
Gross Unrealized Gains	5,387	3,320
Gross Unrealized Losses	(1,504)	(1,936)
Fair Value	1,144,305	1,289,497
Agency Securities [Member]
Amortized Cost	641,997	728,177
Gross Unrealized Gains	4,506	2,134
Gross Unrealized Losses	(279)	(780)
Fair Value	646,224	729,531
Corporate Securities [Member]
Amortized Cost	392,365	453,279
Gross Unrealized Gains	618	933
Gross Unrealized Losses	(1,190)	(1,107)
Fair Value	391,793	453,105
Municipal Securities [Member]
Amortized Cost	80,004	28,681
Gross Unrealized Gains	57	8
Gross Unrealized Losses	(35)	(30)
Fair Value	80,026	28,659
Government Securities [Member]
Amortized Cost	26,056	77,976
Gross Unrealized Gains	206	245
Gross Unrealized Losses	0	(19)
Fair Value	$ 26,262	$ 78,202

For an unclassified balance sheet, this item represents investments in debt and equity securities which are categorized neither as held-to-maturity nor trading.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

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Reference 4: http://www.xbrl.org/2003/role/presentationRef

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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Reference 6: http://www.xbrl.org/2003/role/presentationRef

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-Number 115

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 7: http://www.xbrl.org/2003/role/presentationRef

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Reference 8: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 9: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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+ Details

- Definition

This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

+ References+ Details

- Definition

This item represents the gross unrealized gains for securities, at a point in time, which are categorized neither as held-to-maturity nor trading securities.

+ References+ Details