Fair Value Accounting and Measurement (Financial Assets And Liabilities Accounted for Fair Value On Recurring Basis) (Details) (USD $) In Thousands	Sep. 30, 2011	Dec. 31, 2010
Securities available for sale	$ 995,854	$ 763,866
U.S. Government Agency [Member] \| Fair Value, Inputs, Level 1 [Member] \| Fair Value, Measurements, Recurring [Member]
Securities available for sale	0
U.S. Government Agency [Member] \| Fair Value, Inputs, Level 2 [Member] \| Fair Value, Measurements, Recurring [Member]
Securities available for sale	71,380
U.S. Government Agency [Member] \| Fair Value, Inputs, Level 3 [Member] \| Fair Value, Measurements, Recurring [Member]
Securities available for sale	0
U.S. Government Agency [Member] \| Fair Value, Measurements, Recurring [Member]
Securities available for sale	71,380
U.S. Government Agency and Sponsored Enterprise Mortgage-Back Securities and Collateralized Mortgage Obligations [Member] \| Fair Value, Inputs, Level 1 [Member] \| Fair Value, Measurements, Recurring [Member]
Securities available for sale	0
U.S. Government Agency and Sponsored Enterprise Mortgage-Back Securities and Collateralized Mortgage Obligations [Member] \| Fair Value, Inputs, Level 2 [Member] \| Fair Value, Measurements, Recurring [Member]
Securities available for sale	644,726
U.S. Government Agency and Sponsored Enterprise Mortgage-Back Securities and Collateralized Mortgage Obligations [Member] \| Fair Value, Inputs, Level 3 [Member] \| Fair Value, Measurements, Recurring [Member]
Securities available for sale	0
U.S. Government Agency and Sponsored Enterprise Mortgage-Back Securities and Collateralized Mortgage Obligations [Member] \| Fair Value, Measurements, Recurring [Member]
Securities available for sale	644,726
State and Municipal Debt Securities [Member] \| Fair Value, Inputs, Level 1 [Member] \| Fair Value, Measurements, Recurring [Member]
Securities available for sale	0
State and Municipal Debt Securities [Member] \| Fair Value, Inputs, Level 2 [Member] \| Fair Value, Measurements, Recurring [Member]
Securities available for sale	276,417
State and Municipal Debt Securities [Member] \| Fair Value, Inputs, Level 3 [Member] \| Fair Value, Measurements, Recurring [Member]
Securities available for sale	0
State and Municipal Debt Securities [Member] \| Fair Value, Measurements, Recurring [Member]
Securities available for sale	276,417
Other Securities [Member] \| Fair Value, Inputs, Level 1 [Member] \| Fair Value, Measurements, Recurring [Member]
Securities available for sale	0
Other Securities [Member] \| Fair Value, Inputs, Level 2 [Member] \| Fair Value, Measurements, Recurring [Member]
Securities available for sale	3,331
Other Securities [Member] \| Fair Value, Inputs, Level 3 [Member] \| Fair Value, Measurements, Recurring [Member]
Securities available for sale	0
Other Securities [Member] \| Fair Value, Measurements, Recurring [Member]
Securities available for sale	3,331
Fair Value, Inputs, Level 1 [Member] \| Fair Value, Measurements, Recurring [Member]
Securities available for sale	0
Other assets (Interest rate contracts)	0
Other liabilities (Interest rate contracts)	0
Fair Value, Inputs, Level 2 [Member] \| Fair Value, Measurements, Recurring [Member]
Securities available for sale	995,854
Other assets (Interest rate contracts)	16,463
Other liabilities (Interest rate contracts)	16,463
Fair Value, Inputs, Level 3 [Member] \| Fair Value, Measurements, Recurring [Member]
Securities available for sale	0
Other assets (Interest rate contracts)	0
Other liabilities (Interest rate contracts)	0
Fair Value, Measurements, Recurring [Member]
Securities available for sale	995,854
Other assets (Interest rate contracts)	16,463
Other liabilities (Interest rate contracts)	$ 16,463

Fair Value Accounting and Measurement (Financial Assets And Liabilities Accounted for Fair Value On Recurring Basis) (Details) (USD $)
In Thousands

Sep. 30, 2011

Dec. 31, 2010

$ 995,854

$ 763,866

U.S. Government Agency [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member]

Securities available for sale

U.S. Government Agency [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member]

Securities available for sale

71,380

U.S. Government Agency [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]

Securities available for sale

U.S. Government Agency [Member] | Fair Value, Measurements, Recurring [Member]

Securities available for sale

71,380

U.S. Government Agency and Sponsored Enterprise Mortgage-Back Securities and Collateralized Mortgage Obligations [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member]

Securities available for sale

U.S. Government Agency and Sponsored Enterprise Mortgage-Back Securities and Collateralized Mortgage Obligations [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member]

Securities available for sale

644,726

U.S. Government Agency and Sponsored Enterprise Mortgage-Back Securities and Collateralized Mortgage Obligations [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]

Securities available for sale

U.S. Government Agency and Sponsored Enterprise Mortgage-Back Securities and Collateralized Mortgage Obligations [Member] | Fair Value, Measurements, Recurring [Member]

Securities available for sale

644,726

State and Municipal Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member]

Securities available for sale

State and Municipal Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member]

Securities available for sale

276,417

State and Municipal Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]

Securities available for sale

State and Municipal Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]

Securities available for sale

276,417

Other Securities [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member]

Securities available for sale

Other Securities [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member]

Securities available for sale

3,331

Other Securities [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]

Securities available for sale

Other Securities [Member] | Fair Value, Measurements, Recurring [Member]

Securities available for sale

3,331

Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member]

Securities available for sale

Other assets (Interest rate contracts)

Other liabilities (Interest rate contracts)

Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member]

Securities available for sale

995,854

Other assets (Interest rate contracts)

16,463

Other liabilities (Interest rate contracts)

16,463

Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]

Securities available for sale

Other assets (Interest rate contracts)

Other liabilities (Interest rate contracts)

Fair Value, Measurements, Recurring [Member]

Securities available for sale

995,854

Other assets (Interest rate contracts)

16,463

Other liabilities (Interest rate contracts)

$ 16,463

- Definition

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

+ References

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