Investment Securities (Summary Of Amount Of Gross Unrealized Losses For Debt Securities And Estimated Fair Value) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Investment [Line Items]
Available-for-sale, Less than 12 months - Gross unrealized losses	$ 382	$ 3,414
Available-for-sale, Less than 12 months - Estimated fair value	80,850	369,616
Available-for-sale, 12 months or more - Gross unrealized losses	836,034	921,919
Available-for-sale, 12 months or more - Estimated fair value	864,314	965,952
Available-for-sale, Total - Gross unrealized losses	836,416	925,333
Available-for-sale, Total - Estimated fair value	945,164	1,335,568
Municipal Securities [Member]
Investment [Line Items]
Held-to-maturity, Less than 12 months - Gross unrealized losses	875	415
Held-to-maturity, Less than 12 months - Estimated fair value	22,211	10,855
Held-to-maturity, 12 months or more - Gross unrealized losses	47	668
Held-to-maturity, 12 months or more - Estimated fair value	4,979	22,188
Held-to-maturity, Total - Gross unrealized losses	922	1,083
Held-to-maturity, Total - Estimated fair value	27,190	33,043
Available-for-sale, Less than 12 months - Gross unrealized losses	58	1,305
Available-for-sale, Less than 12 months - Estimated fair value	5,491	15,011
Available-for-sale, 12 months or more - Gross unrealized losses	2,117	395
Available-for-sale, 12 months or more - Estimated fair value	11,401	4,023
Available-for-sale, Total - Gross unrealized losses	2,175	1,700
Available-for-sale, Total - Estimated fair value	16,892	19,034
Agency Securities [Member]
Investment [Line Items]
Available-for-sale, Less than 12 months - Gross unrealized losses	11	60
Available-for-sale, Less than 12 months - Estimated fair value	6,922	13,308
Available-for-sale, 12 months or more - Gross unrealized losses	81	62
Available-for-sale, 12 months or more - Estimated fair value	6,993	3,880
Available-for-sale, Total - Gross unrealized losses	92	122
Available-for-sale, Total - Estimated fair value	13,915	17,188
Agency Guaranteed Mortgage-Backed Securities [Member]
Investment [Line Items]
Available-for-sale, Less than 12 months - Gross unrealized losses	7	102
Available-for-sale, Less than 12 months - Estimated fair value	1,482	52,267
Available-for-sale, 12 months or more - Gross unrealized losses	1	0
Available-for-sale, 12 months or more - Estimated fair value	236	0
Available-for-sale, Total - Gross unrealized losses	8	102
Available-for-sale, Total - Estimated fair value	1,718	52,267
Small Business Administration Loan-Backed Securities [Member]
Investment [Line Items]
Available-for-sale, Less than 12 months - Gross unrealized losses	194	1,783
Available-for-sale, Less than 12 months - Estimated fair value	42,067	260,865
Available-for-sale, 12 months or more - Gross unrealized losses	809	2,713
Available-for-sale, 12 months or more - Estimated fair value	72,357	191,339
Available-for-sale, Total - Gross unrealized losses	1,003	4,496
Available-for-sale, Total - Estimated fair value	114,424	452,204
Mutual Funds And Other [Member]
Investment [Line Items]
Available-for-sale, Less than 12 months - Gross unrealized losses	0	6
Available-for-sale, Less than 12 months - Estimated fair value	0	167
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	0	6
Available-for-sale, Total - Estimated fair value	0	167
Held-To-Maturity [Member]
Investment [Line Items]
Held-to-maturity, Less than 12 months - Gross unrealized losses	875	420
Held-to-maturity, Less than 12 months - Estimated fair value	22,211	10,950
Held-to-maturity, 12 months or more - Gross unrealized losses	154,046	130,654
Held-to-maturity, 12 months or more - Estimated fair value	135,386	179,605
Held-to-maturity, Total - Gross unrealized losses	154,921	131,074
Held-to-maturity, Total - Estimated fair value	157,597	190,555
Available-for-sale Securities [Member]
Investment [Line Items]
Available-for-sale, Less than 12 months - Gross unrealized losses	382	3,408
Available-for-sale, Less than 12 months - Estimated fair value	80,850	369,449
Available-for-sale, 12 months or more - Gross unrealized losses	836,034	921,919
Available-for-sale, 12 months or more - Estimated fair value	864,314	965,952
Available-for-sale, Total - Gross unrealized losses	836,416	925,327
Available-for-sale, Total - Estimated fair value	945,164	1,335,401
Asset-Backed Securities [Member] | Trust Preferred Securities - Banks And Insurance [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	143,572	118,737
Held-to-maturity, 12 months or more - Estimated fair value	118,439	144,053
Held-to-maturity, Total - Gross unrealized losses	143,572	118,737
Held-to-maturity, Total - Estimated fair value	118,439	144,053
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	801,062	880,509
Available-for-sale, 12 months or more - Estimated fair value	739,539	695,365
Available-for-sale, Total - Gross unrealized losses	801,062	880,509
Available-for-sale, Total - Estimated fair value	739,539	695,365
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	10,427	11,249
Held-to-maturity, 12 months or more - Estimated fair value	11,968	13,364
Held-to-maturity, Total - Gross unrealized losses	10,427	11,249
Held-to-maturity, Total - Estimated fair value	11,968	13,364
Available-for-sale, Less than 12 months - Gross unrealized losses	112	0
Available-for-sale, Less than 12 months - Estimated fair value	24,888	0
Available-for-sale, 12 months or more - Gross unrealized losses	6,870	15,302
Available-for-sale, 12 months or more - Estimated fair value	15,337	18,585
Available-for-sale, Total - Gross unrealized losses	6,982	15,302
Available-for-sale, Total - Estimated fair value	40,225	18,585
Asset-Backed Securities [Member] | Other Debt Securities [Member]
Investment [Line Items]
Held-to-maturity, Less than 12 months - Gross unrealized losses		5
Held-to-maturity, Less than 12 months - Estimated fair value		95
Held-to-maturity, 12 months or more - Gross unrealized losses		0
Held-to-maturity, 12 months or more - Estimated fair value		0
Held-to-maturity, Total - Gross unrealized losses		5
Held-to-maturity, Total - Estimated fair value		95
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	25,015	21,614
Available-for-sale, 12 months or more - Estimated fair value	15,407	18,645
Available-for-sale, Total - Gross unrealized losses	25,015	21,614
Available-for-sale, Total - Estimated fair value	15,407	18,645
Asset-Backed Securities [Member] | Auction Rate Securities [Member]
Investment [Line Items]
Available-for-sale, Less than 12 months - Gross unrealized losses	0	158
Available-for-sale, Less than 12 months - Estimated fair value	0	27,998
Available-for-sale, 12 months or more - Gross unrealized losses	79	1,324
Available-for-sale, 12 months or more - Estimated fair value	3,044	34,115
Available-for-sale, Total - Gross unrealized losses	79	1,482
Available-for-sale, Total - Estimated fair value	$ 3,044	$ 62,113