Investment Securities (Summary Of Amount Of Gross Unrealized Losses For Debt Securities And Estimated Fair Value) (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended	12 Months Ended
	Jun. 30, 2013	Dec. 31, 2012
Investment [Line Items]
Available-for-sale, Less than 12 months - Gross unrealized losses	$ 8,714	$ 849
Available-for-sale, Less than 12 months - Estimated fair value	184,683	157,086
Available-for-sale, 12 months or more - Gross unrealized losses	555,737	697,086
Available-for-sale, 12 months or more - Estimated fair value	966,580	887,841
Available-for-sale, Total - Gross unrealized losses	564,451	697,935
Available-for-sale, Total - Estimated fair value	1,151,263	1,044,927
Municipal Securities [Member]
Investment [Line Items]
Held-to-maturity, Less than 12 months - Gross unrealized losses	4,622	630
Held-to-maturity, Less than 12 months - Estimated fair value	102,723	42,613
Held-to-maturity, 12 months or more - Gross unrealized losses	32	79
Held-to-maturity, 12 months or more - Estimated fair value	3,262	5,910
Held-to-maturity, Total - Gross unrealized losses	4,654	709
Held-to-maturity, Total - Estimated fair value	105,985	48,523
Available-for-sale, Less than 12 months - Gross unrealized losses	26	61
Available-for-sale, Less than 12 months - Estimated fair value	2,502	4,898
Available-for-sale, 12 months or more - Gross unrealized losses	1,064	1,909
Available-for-sale, 12 months or more - Estimated fair value	10,391	11,768
Available-for-sale, Total - Gross unrealized losses	1,090	1,970
Available-for-sale, Total - Estimated fair value	12,893	16,666
Agency Securities [Member]
Investment [Line Items]
Available-for-sale, Less than 12 months - Gross unrealized losses	235	35
Available-for-sale, Less than 12 months - Estimated fair value	18,904	18,633
Available-for-sale, 12 months or more - Gross unrealized losses	71	81
Available-for-sale, 12 months or more - Estimated fair value	6,814	6,916
Available-for-sale, Total - Gross unrealized losses	306	116
Available-for-sale, Total - Estimated fair value	25,718	25,549
Agency Guaranteed Mortgage-Backed Securities [Member]
Investment [Line Items]
Available-for-sale, Less than 12 months - Gross unrealized losses	534	10
Available-for-sale, Less than 12 months - Estimated fair value	36,119	6,032
Available-for-sale, 12 months or more - Gross unrealized losses	2	6
Available-for-sale, 12 months or more - Estimated fair value	426	629
Available-for-sale, Total - Gross unrealized losses	536	16
Available-for-sale, Total - Estimated fair value	36,545	6,661
Small Business Administration Loan-Backed Securities [Member]
Investment [Line Items]
Available-for-sale, Less than 12 months - Gross unrealized losses	36	91
Available-for-sale, Less than 12 months - Estimated fair value	4,949	15,199
Available-for-sale, 12 months or more - Gross unrealized losses	467	548
Available-for-sale, 12 months or more - Estimated fair value	41,684	69,011
Available-for-sale, Total - Gross unrealized losses	503	639
Available-for-sale, Total - Estimated fair value	46,633	84,210
Mutual Funds And Other [Member]
Investment [Line Items]
Available-for-sale, Less than 12 months - Gross unrealized losses	7,883	652
Available-for-sale, Less than 12 months - Estimated fair value	122,209	112,324
Available-for-sale, 12 months or more - Gross unrealized losses	0	0
Available-for-sale, 12 months or more - Estimated fair value	0	0
Available-for-sale, Total - Gross unrealized losses	7,883	652
Available-for-sale, Total - Estimated fair value	122,209	112,324
Held-To-Maturity [Member]
Investment [Line Items]
Held-to-maturity, Less than 12 months - Gross unrealized losses	4,705	630
Held-to-maturity, Less than 12 months - Estimated fair value	102,799	42,613
Held-to-maturity, 12 months or more - Gross unrealized losses	121,371	140,632
Held-to-maturity, 12 months or more - Estimated fair value	165,774	142,833
Held-to-maturity, Total - Gross unrealized losses	126,076	141,262
Held-to-maturity, Total - Estimated fair value	268,573	185,446
Available-for-sale Securities [Member]
Investment [Line Items]
Available-for-sale, Less than 12 months - Gross unrealized losses	831	197
Available-for-sale, Less than 12 months - Estimated fair value	62,474	44,762
Available-for-sale, 12 months or more - Gross unrealized losses	555,737	697,086
Available-for-sale, 12 months or more - Estimated fair value	966,580	887,841
Available-for-sale, Total - Gross unrealized losses	556,568	697,283
Available-for-sale, Total - Estimated fair value	1,029,054	932,603
Asset-Backed Securities [Member] | Trust Preferred Securities - Banks And Insurance [Member]
Investment [Line Items]
Held-to-maturity, Less than 12 months - Gross unrealized losses	83	0
Held-to-maturity, Less than 12 months - Estimated fair value	76	0
Held-to-maturity, 12 months or more - Gross unrealized losses	111,100	129,560
Held-to-maturity, 12 months or more - Estimated fair value	151,156	126,019
Held-to-maturity, Total - Gross unrealized losses	111,183	129,560
Held-to-maturity, Total - Estimated fair value	151,232	126,019
Available-for-sale, Less than 12 months - Gross unrealized losses	0	0
Available-for-sale, Less than 12 months - Estimated fair value	0	0
Available-for-sale, 12 months or more - Gross unrealized losses	529,836	663,451
Available-for-sale, 12 months or more - Estimated fair value	868,996	765,421
Available-for-sale, Total - Gross unrealized losses	529,836	663,451
Available-for-sale, Total - Estimated fair value	868,996	765,421
Asset-Backed Securities [Member] | Other [Member]
Investment [Line Items]
Held-to-maturity, Less than 12 months - Gross unrealized losses	0	0
Held-to-maturity, Less than 12 months - Estimated fair value	0	0
Held-to-maturity, 12 months or more - Gross unrealized losses	10,239	10,993
Held-to-maturity, 12 months or more - Estimated fair value	11,356	10,904
Held-to-maturity, Total - Gross unrealized losses	10,239	10,993
Held-to-maturity, Total - Estimated fair value	11,356	10,904
Available-for-sale, Less than 12 months - Gross unrealized losses	0	0
Available-for-sale, Less than 12 months - Estimated fair value	0	0
Available-for-sale, 12 months or more - Gross unrealized losses	2,311	6,941
Available-for-sale, 12 months or more - Estimated fair value	17,287	15,234
Available-for-sale, Total - Gross unrealized losses	2,311	6,941
Available-for-sale, Total - Estimated fair value	17,287	15,234
Asset-Backed Securities [Member] | Trust Preferred Securities - Real Estate Investment Trusts [Member]
Investment [Line Items]
Available-for-sale, Less than 12 months - Gross unrealized losses	0	0
Available-for-sale, Less than 12 months - Estimated fair value	0	0
Available-for-sale, 12 months or more - Gross unrealized losses	21,942	24,082
Available-for-sale, 12 months or more - Estimated fair value	18,499	16,403
Available-for-sale, Total - Gross unrealized losses	21,942	24,082
Available-for-sale, Total - Estimated fair value	18,499	16,403
Asset-Backed Securities [Member] | Auction Rate Securities [Member]
Investment [Line Items]
Available-for-sale, Less than 12 months - Gross unrealized losses	0	0
Available-for-sale, Less than 12 months - Estimated fair value	0	0
Available-for-sale, 12 months or more - Gross unrealized losses	44	68
Available-for-sale, 12 months or more - Estimated fair value	2,483	2,459
Available-for-sale, Total - Gross unrealized losses	44	68
Available-for-sale, Total - Estimated fair value	$ 2,483	$ 2,459