Fair Value (Schedule Of Financial Assets And Liabilities Measured At Fair Value On Recurring Basis) (Details) (USD $) In Thousands	Jun. 30, 2011	Dec. 31, 2010
Total available for sale securities, Fair Value	$ 4,573,973	$ 1,488,885
Other short-term investments		274,974
Total assets	4,582,612	1,766,811
Total Liabilities	8,716	2,952
Level 1 [Member]
Other short-term investments		274,974
Total assets	460,285	411,679
Total Liabilities
Level 1 [Member] \| Debt Securities Issued By The U.S. Treasury And Other Government Corporations And Agencies [Member]
Total available for sale securities, Fair Value	436,331	117,435
Level 1 [Member] \| Debt Securities Issued By States Of The United States And Political Subdivisions Of The States [Member]
Total available for sale securities, Fair Value
Level 1 [Member] \| Corporate Debt Securities [Member]
Total available for sale securities, Fair Value	18,884	15,285
Level 1 [Member] \| Residential Mortgage-Backed Securities [Member]
Total available for sale securities, Fair Value
Level 1 [Member] \| Collateralized Mortgage Obligations [Member]
Total available for sale securities, Fair Value
Level 1 [Member] \| Equity Securities [Member]
Total available for sale securities, Fair Value	5,070	3,985
Level 1 [Member] \| Derivative Financial Instruments, Assets [Member]
Total available for sale securities, Fair Value
Level 1 [Member] \| Derivative Financial Instruments, Liabilities [Member]
Total available for sale securities, Fair Value
Total Liabilities
Level 2 [Member]
Other short-term investments
Total assets	4,122,327	1,355,132
Total Liabilities	8,716	2,952
Level 2 [Member] \| Debt Securities Issued By The U.S. Treasury And Other Government Corporations And Agencies [Member]
Total available for sale securities, Fair Value
Level 2 [Member] \| Debt Securities Issued By States Of The United States And Political Subdivisions Of The States [Member]
Total available for sale securities, Fair Value	318,836	180,443
Level 2 [Member] \| Corporate Debt Securities [Member]
Total available for sale securities, Fair Value
Level 2 [Member] \| Residential Mortgage-Backed Securities [Member]
Total available for sale securities, Fair Value	2,285,127	799,686
Level 2 [Member] \| Collateralized Mortgage Obligations [Member]
Total available for sale securities, Fair Value	1,509,725	372,051
Level 2 [Member] \| Equity Securities [Member]
Total available for sale securities, Fair Value
Level 2 [Member] \| Derivative Financial Instruments, Assets [Member]
Total available for sale securities, Fair Value	8,639	2,952
Level 2 [Member] \| Derivative Financial Instruments, Liabilities [Member]
Total available for sale securities, Fair Value		2,952
Total Liabilities	8,716
Debt Securities Issued By The U.S. Treasury And Other Government Corporations And Agencies [Member]
Total available for sale securities, Fair Value	436,331	117,435
Debt Securities Issued By States Of The United States And Political Subdivisions Of The States [Member]
Total available for sale securities, Fair Value	318,836	180,443
Corporate Debt Securities [Member]
Total available for sale securities, Fair Value	18,884	15,285
Residential Mortgage-Backed Securities [Member]
Total available for sale securities, Fair Value	2,285,127	799,686
Collateralized Mortgage Obligations [Member]
Total available for sale securities, Fair Value	1,509,725	372,051
Equity Securities [Member]
Total available for sale securities, Fair Value	5,070	3,985
Derivative Financial Instruments, Assets [Member]
Total available for sale securities, Fair Value	8,639	2,952
Derivative Financial Instruments, Liabilities [Member]
Total available for sale securities, Fair Value		2,952
Total Liabilities	$ 8,716

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
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6871852&loc=d3e26610-111562

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 115
-Paragraph 12
-Subparagraph b
-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 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Staff Position (FSP)
-Number FAS115-1/124-1
-Paragraph 15E
-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 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 133
-Paragraph 22
-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 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Staff Position (FSP)
-Number FAS115-1/124-1
-Paragraph 15D
-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 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 115
-Paragraph 13
-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
-Publisher FASB
-Name FASB Staff Position (FSP)
-Number FAS115-1/124-1
-Paragraph 15C
-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 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 115
-Paragraph 14
-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)
-Number 115
-Paragraph 16
-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 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 25
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6379932&loc=d3e22054-111558

+ Details

- Definition

Other investments not otherwise specified in the taxonomy that will be realized in a short period of time, usually less than one year or the normal operating cycle, whichever is longer.

+ References+ Details