Investment Securities (Summary Of Amount Of Gross Unrealized Losses For Debt Securities And Estimated Fair Value) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Investment [Line Items]
Available-for-sale, Less than 12 months - Gross unrealized losses	$ 1,173	$ 3,414
Available-for-sale, Less than 12 months - Estimated fair value	189,639	369,616
Available-for-sale, 12 months or more - Gross unrealized losses	892,213	921,919
Available-for-sale, 12 months or more - Estimated fair value	1,034,766	965,952
Available-for-sale, Total - Gross unrealized losses	893,386	925,333
Available-for-sale, Total - Estimated fair value	1,224,405	1,335,568
Municipal Securities [Member]
Investment [Line Items]
Held-to-maturity, Less than 12 months - Gross unrealized losses	287	415
Held-to-maturity, Less than 12 months - Estimated fair value	8,471	10,855
Held-to-maturity, 12 months or more - Gross unrealized losses	555	668
Held-to-maturity, 12 months or more - Estimated fair value	18,711	22,188
Held-to-maturity, Total - Gross unrealized losses	842	1,083
Held-to-maturity, Total - Estimated fair value	27,182	33,043
Available-for-sale, Less than 12 months - Gross unrealized losses	45	1,305
Available-for-sale, Less than 12 months - Estimated fair value	2,546	15,011
Available-for-sale, 12 months or more - Gross unrealized losses	1,653	395
Available-for-sale, 12 months or more - Estimated fair value	12,027	4,023
Available-for-sale, Total - Gross unrealized losses	1,698	1,700
Available-for-sale, Total - Estimated fair value	14,573	19,034
Agency Securities [Member]
Investment [Line Items]
Available-for-sale, Less than 12 months - Gross unrealized losses	77	60
Available-for-sale, Less than 12 months - Estimated fair value	22,442	13,308
Available-for-sale, 12 months or more - Gross unrealized losses	65	62
Available-for-sale, 12 months or more - Estimated fair value	3,823	3,880
Available-for-sale, Total - Gross unrealized losses	142	122
Available-for-sale, Total - Estimated fair value	26,265	17,188
Agency Guaranteed Mortgage-Backed Securities [Member]
Investment [Line Items]
Available-for-sale, Less than 12 months - Gross unrealized losses	44	102
Available-for-sale, Less than 12 months - Estimated fair value	10,224	52,267
Available-for-sale, 12 months or more - Gross unrealized losses	3
Available-for-sale, 12 months or more - Estimated fair value	587
Available-for-sale, Total - Gross unrealized losses	47	102
Available-for-sale, Total - Estimated fair value	10,811	52,267
Small Business Administration Loan-Backed Securities [Member]
Investment [Line Items]
Available-for-sale, Less than 12 months - Gross unrealized losses	576	1,783
Available-for-sale, Less than 12 months - Estimated fair value	106,460	260,865
Available-for-sale, 12 months or more - Gross unrealized losses	2,416	2,713
Available-for-sale, 12 months or more - Estimated fair value	262,749	191,339
Available-for-sale, Total - Gross unrealized losses	2,992	4,496
Available-for-sale, Total - Estimated fair value	369,209	452,204
Mutual Funds And Other [Member]
Investment [Line Items]
Available-for-sale, Less than 12 months - Gross unrealized losses		6
Available-for-sale, Less than 12 months - Estimated fair value		167
Available-for-sale, Total - Gross unrealized losses		6
Available-for-sale, Total - Estimated fair value		167
Available-For-Sale Securities [Member]
Investment [Line Items]
Available-for-sale, Less than 12 months - Gross unrealized losses		3,408
Available-for-sale, Less than 12 months - Estimated fair value		369,449
Available-for-sale, 12 months or more - Gross unrealized losses		921,919
Available-for-sale, 12 months or more - Estimated fair value		965,952
Available-for-sale, Total - Gross unrealized losses		925,327
Available-for-sale, Total - Estimated fair value		1,335,401
Asset-Backed Securities [Member] | Trust Preferred Securities - Banks And Insurance [Member]
Investment [Line Items]
Held-to-maturity, 12 months or more - Gross unrealized losses	116,060	118,737
Held-to-maturity, 12 months or more - Estimated fair value	147,151	144,053
Held-to-maturity, Total - Gross unrealized losses	116,060	118,737
Held-to-maturity, Total - Estimated fair value	147,151	144,053
Available-for-sale, Less than 12 months - Gross unrealized losses	302
Available-for-sale, Less than 12 months - Estimated fair value	37,960
Available-for-sale, 12 months or more - Gross unrealized losses	853,169	880,509
Available-for-sale, 12 months or more - Estimated fair value	707,424	695,365
Available-for-sale, Total - Gross unrealized losses	853,471	880,509
Available-for-sale, Total - Estimated fair value	745,384	695,365
Asset-Backed Securities [Member] | Other (including ABS CDOs) [Member]
Investment [Line Items]
Held-to-maturity, 12 months or more - Gross unrealized losses	11,517	11,249
Held-to-maturity, 12 months or more - Estimated fair value	12,091	13,364
Held-to-maturity, Total - Gross unrealized losses	11,517	11,249
Held-to-maturity, Total - Estimated fair value	12,091	13,364
Available-for-sale, 12 months or more - Gross unrealized losses	10,025	15,302
Available-for-sale, 12 months or more - Estimated fair value	15,331	18,585
Available-for-sale, Total - Gross unrealized losses	10,025	15,302
Available-for-sale, Total - Estimated fair value	15,331	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, 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, 12 months or more - Gross unrealized losses	24,300	21,614
Available-for-sale, 12 months or more - Estimated fair value	16,001	18,645
Available-for-sale, Total - Gross unrealized losses	24,300	21,614
Available-for-sale, Total - Estimated fair value	16,001	18,645
Asset-Backed Securities [Member] | Auction Rate Securities [Member]
Investment [Line Items]
Available-for-sale, Less than 12 months - Gross unrealized losses	129	158
Available-for-sale, Less than 12 months - Estimated fair value	10,007	27,998
Available-for-sale, 12 months or more - Gross unrealized losses	582	1,324
Available-for-sale, 12 months or more - Estimated fair value	16,824	34,115
Available-for-sale, Total - Gross unrealized losses	711	1,482
Available-for-sale, Total - Estimated fair value	26,831	62,113
Held-To-Maturity [Member]
Investment [Line Items]
Held-to-maturity, Less than 12 months - Gross unrealized losses	287	420
Held-to-maturity, Less than 12 months - Estimated fair value	8,471	10,950
Held-to-maturity, 12 months or more - Gross unrealized losses	128,132	130,654
Held-to-maturity, 12 months or more - Estimated fair value	177,953	179,605
Held-to-maturity, Total - Gross unrealized losses	128,419	131,074
Held-to-maturity, Total - Estimated fair value	$ 186,424	$ 190,555