Investment Securities (Summary Of Available For Sale Investment Securities By Maturity Groupings) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Investment [Line Items]
Amortized Cost	$ 8,721,015	$ 9,012,095
Fair Value	9,020,951	9,224,702
U.S. Government And Federal Agency Obligations [Member]
Investment [Line Items]
Amortized Cost	324,475	328,530
Fair Value	367,497	364,665
U.S. Government And Federal Agency Obligations [Member] \| Available-For-Sale Securities, Maturity Within 1 Year [Member]
Investment [Line Items]
Amortized Cost	500
Fair Value	500
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	217,296
Fair Value	241,881
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	106,679
Fair Value	125,116
Government-Sponsored Enterprise Obligations [Member]
Investment [Line Items]
Amortized Cost	374,525	311,529
Fair Value	380,190	315,698
Government-Sponsored Enterprise Obligations [Member] \| Available-For-Sale Securities, Maturity After 1 But Within 5 Years [Member]
Investment [Line Items]
Amortized Cost	108,506
Fair Value	112,286
Government-Sponsored Enterprise Obligations [Member] \| Available-For-Sale Securities, Maturity After 5 But Within 10 Years [Member]
Investment [Line Items]
Amortized Cost	74,682
Fair Value	75,436
Government-Sponsored Enterprise Obligations [Member] \| Available-For-Sale Securities, Maturity After 10 Years [Member]
Investment [Line Items]
Amortized Cost	191,337
Fair Value	192,468
State And Municipal Obligations [Member]
Investment [Line Items]
Amortized Cost	1,426,059	1,220,840
Fair Value	1,461,251	1,245,284
State And Municipal Obligations [Member] \| Available-For-Sale Securities, Maturity Within 1 Year [Member]
Investment [Line Items]
Amortized Cost	92,856
Fair Value	93,592
State And Municipal Obligations [Member] \| Available-For-Sale Securities, Maturity After 1 But Within 5 Years [Member]
Investment [Line Items]
Amortized Cost	629,641
Fair Value	655,509
State And Municipal Obligations [Member] \| Available-For-Sale Securities, Maturity After 5 But Within 10 Years [Member]
Investment [Line Items]
Amortized Cost	510,060
Fair Value	528,245
State And Municipal Obligations [Member] \| Available-For-Sale Securities, Maturity After 10 Years [Member]
Investment [Line Items]
Amortized Cost	193,502
Fair Value	183,905
Agency Mortgage-Backed Securities [Member]
Investment [Line Items]
Amortized Cost	3,311,100	3,989,464
Fair Value	3,471,262	4,106,059
Non-Agency Mortgage-Backed Securities [Member]
Investment [Line Items]
Amortized Cost	241,657	315,752
Fair Value	255,172	316,902
Asset-Backed Securities [Member]
Investment [Line Items]
Amortized Cost	2,917,206	2,692,436
Fair Value	2,930,810	2,693,143
Total Mortgage And Asset-Backed Securities [Member]
Investment [Line Items]
Amortized Cost	6,469,963	6,997,652
Fair Value	6,657,244	7,116,104
Other Debt Securities [Member]
Investment [Line Items]
Amortized Cost	117,510	135,190
Fair Value	121,623	141,260
Other Debt Securities [Member] \| Available-For-Sale Securities, Maturity Within 1 Year [Member]
Investment [Line Items]
Amortized Cost	45,809
Fair Value	46,574
Other Debt Securities [Member] \| Available-For-Sale Securities, Maturity After 1 But Within 5 Years [Member]
Investment [Line Items]
Amortized Cost	60,744
Fair Value	63,898
Other Debt Securities [Member] \| Available-For-Sale Securities, Maturity After 5 But Within 10 Years [Member]
Investment [Line Items]
Amortized Cost	3,969
Fair Value	4,047
Other Debt Securities [Member] \| Available-For-Sale Securities, Maturity After 10 Years [Member]
Investment [Line Items]
Amortized Cost	6,988
Fair Value	7,104
Equity Securities [Member]
Investment [Line Items]
Amortized Cost	8,483	18,354
Fair Value	$ 33,146	$ 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