Fair Value (Schedule Of Assets And Liabilities Measured At Fair Value By Class On A Recurring Basis Using Level 3 Inputs) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total net gains (losses) included in, Other noninterest expense	$ 67,426	$ 72,773	$ 130,717	$ 139,524
Municipal Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of assets, Beginning balance	17,109	19,057	17,381	22,289
Total net gains (losses) included in, Accretion of purchase discount on securities available-for-sale	21	21	64	190
Total net gains (losses) included in, Fixed income securities gains (losses), net				18
Total net gains (losses) included in, Other comprehensive income (loss)	(595)	(216)	(635)	(515)
Total net gains (losses) included in, Sales				(895)
Total net gains (losses) included in, Redemptions and paydowns	(175)		(450)	(2,225)
Fair value of assets, Ending balance	16,360	18,862	16,360	18,862
Trust Preferred - Banks And Insurance [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of assets, Beginning balance	935,870	1,183,999	929,356	1,241,694
Total net gains (losses) included in, Accretion of purchase discount on securities available-for-sale	2,475	1,413	5,028	2,890
Total net gains (losses) included in, Fixed income securities gains (losses), net	3,224	3,595	7,776	7,063
Total net gains (losses) included in, Net impairment losses on investment securities	(6,967)	(3,046)	(17,176)	(4,866)
Total net gains (losses) included in, Other comprehensive income (loss)	3,534	(6,852)	33,733	(57,893)
Total net gains (losses) included in, Sales		(71,940)		(72,881)
Total net gains (losses) included in, Redemptions and paydowns	(11,686)	(9,252)	(32,267)	(18,090)
Fair value of assets, Ending balance	926,450	1,097,917	926,450	1,097,917
Trust Preferred Securities - Real Estate Investment Trusts [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of assets, Beginning balance	16,000	19,714	18,645	19,165
Total net gains (losses) included in, Accretion of purchase discount on securities available-for-sale	61		101
Total net gains (losses) included in, Fixed income securities gains (losses), net				(3,605)
Total net gains (losses) included in, Net impairment losses on investment securities				(1,285)
Total net gains (losses) included in, Other comprehensive income (loss)	(1,630)	(583)	(4,315)	5,394
Total net gains (losses) included in, Sales				(538)
Fair value of assets, Ending balance	14,431	19,131	14,431	19,131
Auction Rate Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of assets, Beginning balance	40,873	109,244	70,020	109,609
Total net gains (losses) included in, Accretion of purchase discount on securities available-for-sale	1	1	2	9
Total net gains (losses) included in, Fixed income securities gains (losses), net	2,246	875	4,134	882
Total net gains (losses) included in, Other comprehensive income (loss)	546	(41)	1,335	(61)
Total net gains (losses) included in, Sales				(135)
Total net gains (losses) included in, Redemptions and paydowns	(36,500)	(18,975)	(68,325)	(19,200)
Fair value of assets, Ending balance	7,166	91,104	7,166	91,104
Other Asset-Backed [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of assets, Beginning balance	40,322	69,487	43,546	69,630
Total net gains (losses) included in, Accretion of purchase discount on securities available-for-sale	80	34	160	73
Total net gains (losses) included in, Fixed income securities gains (losses), net		(6,935)	(5,773)	(6,928)
Total net gains (losses) included in, Net impairment losses on investment securities				(2,112)
Total net gains (losses) included in, Other comprehensive income (loss)	569	5,076	5,883	6,400
Total net gains (losses) included in, Sales		19,310		(19,310)
Total net gains (losses) included in, Redemptions and paydowns	(305)	(864)	(3,150)	(2,377)
Fair value of assets, Ending balance	40,666	45,376	40,666	45,376
Private Equity Investments [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of assets, Beginning balance	134,746	142,547	128,348	141,690
Total net gains (losses) included in, Dividends and other investment income	6,820	4,858	8,559	5,565
Total net gains (losses) included in, Equity securities gains, net	(10,086)	(1,635)	(625)	(738)
Total net gains (losses) included in, Purchases	4,397	9,466	7,379	12,799
Total net gains (losses) included in, Sales	(9,064)	(4,009)	(14,718)	(7,286)
Total net gains (losses) included in, Redemptions and paydowns	(5,325)	(15,148)	(7,455)	(15,951)
Fair value of assets, Ending balance	121,488	136,079	121,488	136,079
Derivatives [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of liabilities, Beginning balance	(5,218)	(10,511)	(5,422)	(15,925)
Total net gains (losses) included, in Redemptions and paydowns, Liabilities	119	5,091	85	10,505
Fair value of liabilities, Ending balance	(5,337)	(5,420)	(5,337)	(5,420)
Other Liabilities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of liabilities, Beginning balance	(205)	(442)	(86)	(561)
Total net gains (losses) included in, Other noninterest expense	84		(35)	119
Fair value of liabilities, Ending balance	$ (121)	$ (442)	$ (121)	$ (442)