Investment Securities (Summary Of Available For Sale Investment Securities By Maturity Groupings) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Investment [Line Items]
Amortized Cost	$ 8,953,056	$ 9,012,095
Fair Value	9,206,451	9,224,702
U.S. Government And Federal Agency Obligations [Member]
Investment [Line Items]
Amortized Cost	333,527	328,530
Fair Value	370,123	364,665
U.S. Government And Federal Agency Obligations [Member] \| Available-For-Sale Securities, Maturity Within 1 Year [Member]
Investment [Line Items]
Amortized Cost	7,962
Fair Value	8,014
U.S. Government And Federal Agency Obligations [Member] \| Available-For-Sale Securities, Maturity After 1 But Within 5 Years [Member]
Investment [Line Items]
Amortized Cost	189,657
Fair Value	206,839
U.S. Government And Federal Agency Obligations [Member] \| Available-For-Sale Securities, Maturity After 5 But Within 10 Years [Member]
Investment [Line Items]
Amortized Cost	135,908
Fair Value	155,270
Government-Sponsored Enterprise Obligations [Member]
Investment [Line Items]
Amortized Cost	262,504	311,529
Fair Value	266,702	315,698
Government-Sponsored Enterprise Obligations [Member] \| Available-For-Sale Securities, Maturity After 1 But Within 5 Years [Member]
Investment [Line Items]
Amortized Cost	108,745
Fair Value	112,338
Government-Sponsored Enterprise Obligations [Member] \| Available-For-Sale Securities, Maturity After 5 But Within 10 Years [Member]
Investment [Line Items]
Amortized Cost	28,318
Fair Value	28,561
Government-Sponsored Enterprise Obligations [Member] \| Available-For-Sale Securities, Maturity After 10 Years [Member]
Investment [Line Items]
Amortized Cost	125,441
Fair Value	125,803
State And Municipal Obligations [Member]
Investment [Line Items]
Amortized Cost	1,332,766	1,220,840
Fair Value	1,358,537	1,245,284
State And Municipal Obligations [Member] \| Available-For-Sale Securities, Maturity Within 1 Year [Member]
Investment [Line Items]
Amortized Cost	87,437
Fair Value	88,192
State And Municipal Obligations [Member] \| Available-For-Sale Securities, Maturity After 1 But Within 5 Years [Member]
Investment [Line Items]
Amortized Cost	591,654
Fair Value	614,243
State And Municipal Obligations [Member] \| Available-For-Sale Securities, Maturity After 5 But Within 10 Years [Member]
Investment [Line Items]
Amortized Cost	453,346
Fair Value	468,436
State And Municipal Obligations [Member] \| Available-For-Sale Securities, Maturity After 10 Years [Member]
Investment [Line Items]
Amortized Cost	200,329
Fair Value	187,666
Agency Mortgage-Backed Securities [Member]
Investment [Line Items]
Amortized Cost	3,660,014	3,989,464
Fair Value	3,802,110	4,106,059
Non-Agency Mortgage-Backed Securities [Member]
Investment [Line Items]
Amortized Cost	262,191	315,752
Fair Value	269,304	316,902
Asset-Backed Securities [Member]
Investment [Line Items]
Amortized Cost	2,981,425	2,692,436
Fair Value	2,991,092	2,693,143
Total Mortgage And Asset-Backed Securities [Member]
Investment [Line Items]
Amortized Cost	6,903,630	6,997,652
Fair Value	7,062,506	7,116,104
Other Debt Securities [Member]
Investment [Line Items]
Amortized Cost	106,494	135,190
Fair Value	110,814	141,260
Other Debt Securities [Member] \| Available-For-Sale Securities, Maturity Within 1 Year [Member]
Investment [Line Items]
Amortized Cost	36,708
Fair Value	37,495
Other Debt Securities [Member] \| Available-For-Sale Securities, Maturity After 1 But Within 5 Years [Member]
Investment [Line Items]
Amortized Cost	69,786
Fair Value	73,319
Equity Securities [Member]
Investment [Line Items]
Amortized Cost	14,135	18,354
Fair Value	$ 37,769	$ 41,691

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

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