Investment Securities (Amortized Cost And Fair Value Of Available-For-Sale And Held-To-Maturity Investment Securities Portfolio) (Details) (USD $) In Thousands	6 Months Ended	12 Months Ended
Jun. 30, 2011	Dec. 31, 2010	Jun. 30, 2010
Available-for-sale, Amortized Cost	$ 2,168,082	$ 1,953,842
Available-for-sale, Unrealized Gains	56,900	41,246
Available-for-sale, Unrealized Losses	(22,127)	(34,866)
Available-for-sale, Fair Value	2,202,855	1,960,222	2,264,467
Held-to-maturity, Amortized Cost	567,708	638,210	582,068
Held-to-maturity, Unrealized Gains	9,765	4,825
Held-to-maturity, Unrealized Losses	(3,299)	(17,392)
Held-to-maturity, Fair Value	574,174	625,643	596,614
U.S. Treasury [Member]
Available-for-sale, Amortized Cost	62,331	62,206
Available-for-sale, Unrealized Gains	415	371
Available-for-sale, Unrealized Losses	0	(27)
Available-for-sale, Fair Value	62,746	62,550
US Government-Sponsored Entities And Agencies [Member]
Available-for-sale, Amortized Cost	384,508	315,922
Available-for-sale, Unrealized Gains	2,811	1,612
Available-for-sale, Unrealized Losses	(108)	(2,401)
Available-for-sale, Fair Value	387,211	315,133
Held-to-maturity, Amortized Cost	245,301	303,265
Held-to-maturity, Unrealized Gains	5,092	2,247
Held-to-maturity, Unrealized Losses	(85)	(3,703)
Held-to-maturity, Fair Value	250,308	301,809
Mortgage-Backed Securities, Issued By US Government Sponsored Enterprises [Member]
Available-for-sale, Amortized Cost	1,075,830	922,005
Available-for-sale, Unrealized Gains	28,372	22,926
Available-for-sale, Unrealized Losses	(113)	(485)
Available-for-sale, Fair Value	1,104,089	944,446
Held-to-maturity, Amortized Cost	98,374	117,013
Held-to-maturity, Unrealized Gains	3,424	2,577
Held-to-maturity, Unrealized Losses	0	(510)
Held-to-maturity, Fair Value	101,798	119,080
Mortgage-Backed Securities - Non-Agency Group 1 [Member]
Available-for-sale, Amortized Cost	40,955	134,168	120,823
Available-for-sale, Unrealized Gains		1,018
Available-for-sale, Unrealized Losses		(8,380)
Available-for-sale, Fair Value		126,806
Mortgage-Backed Securities - Non-Agency [Member]
Available-for-sale, Amortized Cost	105,533
Available-for-sale, Unrealized Gains	740
Available-for-sale, Unrealized Losses	(2,738)
Available-for-sale, Fair Value	103,535
States And Political Subdivisions [Member]
Available-for-sale, Amortized Cost	353,949	343,970
Available-for-sale, Unrealized Gains	15,112	7,503
Available-for-sale, Unrealized Losses	(640)	(2,549)
Available-for-sale, Fair Value	368,421	348,924
Held-to-maturity, Amortized Cost	216,894	217,381
Held-to-maturity, Unrealized Gains	1,249	1
Held-to-maturity, Unrealized Losses	(3,199)	(13,003)
Held-to-maturity, Fair Value	214,944	204,379
Pooled Trust Preferred Securities Group 1 [Member]
Available-for-sale, Amortized Cost	27,349	27,368	3,403
Available-for-sale, Unrealized Gains	0	0
Available-for-sale, Unrealized Losses	(17,611)	(18,968)
Available-for-sale, Fair Value	9,738	8,400
Other Securities [Member]
Available-for-sale, Amortized Cost	158,582	148,203
Available-for-sale, Unrealized Gains	9,450	7,816
Available-for-sale, Unrealized Losses	(917)	(2,056)
Available-for-sale, Fair Value	167,115	153,963
Held-to-maturity, Amortized Cost	7,139	551
Held-to-maturity, Unrealized Gains	0	0
Held-to-maturity, Unrealized Losses	(15)	(176)
Held-to-maturity, Fair Value	$ 7,124	$ 375

For an unclassified balance sheet, this item represents investments in debt and equity securities which are categorized neither as held-to-maturity nor trading. Such securities are reported at fair value, with unrealized gains and losses excluded from earnings and reported in a separate component of shareholders' equity (other comprehensive income), unless the Available-for-sale Security is designated as a hedge or is determined to have had an other than temporary decline in fair value below its amortized cost basis. All or a portion of the unrealized holding gain or loss of an Available-for-sale Security that is designated as being hedged in a fair value hedge shall be recognized in earnings during the period of the hedge, as should other than temporary declines in fair value below costs basis.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 115
-Paragraph 16

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 133
-Paragraph 22

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 115
-Paragraph 12
-Subparagraph b

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 115
-Paragraph 13

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 115
-Paragraph 14

+ Details

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Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments made for accretion, amortization, other-than-temporary impairments, and hedging, if any.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Staff Position (FSP)
-Number FAS115-1/124-1
-Paragraph 7
-Footnote 2

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 115
-Paragraph 19

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

This item represents the gross unrealized gains for securities which are categorized neither as held-to-maturity nor trading securities. Such gross unrealized gains are the excess of the fair value of the Available-for-sale Securities over their carrying value as of the reporting date. Such gross unrealized gains are included in other comprehensive income in the statement of shareholders' equity, unless the Available-for-sale Security is designated as a hedge. All or a portion of the unrealized holding gain of an available-for-sale security that is designated as being hedged in a fair value hedge shall be recognized in earnings during the period of the hedge.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 133
-Paragraph 22

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 115
-Paragraph 13, 19

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- Definition

This item represents the gross unrealized losses for securities which are categorized neither as held-to-maturity nor trading securities. Such gross unrealized losses are the excess of the carrying value of the Available-for-sale Securities over their fair value as of the reporting date. Such gross unrealized losses are included in other comprehensive income in the statement of shareholders' equity, unless the Available-for-sale Security is designated as a hedge or is determined to have had an other than temporary decline in fair value below its amortized cost basis. All or a portion of the unrealized holding loss of an Available-for-sale Security that is designated as being hedged in a fair value hedge shall be recognized in earnings during the period of the hedge, as should other than temporary declines in fair value below costs basis.

+ References

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- Definition

For an unclassified balance sheet, this item represents investments in debt securities which are categorized as held-to-maturity; such investments are measured at amortized cost (carrying value). The held-to-maturity category is for those securities that the Entity has the positive intent and ability to hold until maturity.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 43
-Chapter 3
-Section A
-Paragraph 4, 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 115
-Paragraph 17

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 115
-Paragraph 7, 8, 9, 10, 11

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Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

This item represents the aggregate fair value of investments in debt securities as of the balance sheet date and which are categorized as held-to-maturity.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 115
-Paragraph 19

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 115
-Paragraph 137

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- Definition

As of the balance sheet date, the excess of fair value over carrying value (amortized cost) of a debt security categorized as held-to-maturity, exclusive of dividend or interest income recognized but not yet received and exclusive of any write-downs for other-than-temporary impairment. Such item represents the gross unrecognized holding gain.

+ References

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- Definition

As of the balance sheet date, the excess of carrying value (amortized cost) over fair value of a debt security categorized as held-to-maturity, exclusive of dividend or interest income recognized but not yet received and exclusive of any write-downs for other-than-temporary impairment. Such item represents the gross unrecognized holding loss.

+ References

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