Business Segments (Schedule Of Financial Data For Business Segments) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Average interest earning assets	$ 12,814,236				$ 12,679,756				$ 12,814,236	$ 12,679,756	$ 13,031,646
Interest income	166,572	171,639	167,794	167,819	165,090	170,586	171,187	169,949	673,824	676,812	712,184
Interest expense	48,258	49,704	50,124	50,927	51,949	52,852	54,161	55,098	199,013	214,060	262,870
Net interest income (loss)	118,314	121,935	117,670	116,892	113,141	117,734	117,026	114,851	474,811	462,752	449,314
Provision for credit losses	15,364	7,783	6,026	24,162	15,099	9,308	12,438	12,611	53,335	49,456	47,992
Net interest income (loss) after provision for credit losses									421,476	413,296	401,322
Non-interest income									112,297	91,327	72,251
Non-interest expense	84,377	85,302	83,080	83,829	80,408	78,947	79,973	78,354	336,588	317,682	306,028
Income (loss) before income taxes	32,345	49,053	62,099	53,688	53,480	46,807	47,091	39,563	197,185	186,941	167,545
Return on average interest earning assets (pre-tax)	1.54%				1.47%				1.54%	1.47%	1.29%
Customer Lending [Member]
Average interest earning assets	6,214,319				3,321,124				6,214,319	3,321,124	3,775,689
Interest income									375,873	180,432	213,310
Interest expense									87,574	51,240	70,822
Net interest income (loss)									288,299	129,192	142,488
Provision for credit losses									46,529	14,598	21,176
Net interest income (loss) after provision for credit losses									241,770	114,594	121,312
Non-interest income									16,965	52,545	48,233
Non-interest expense									48,829	49,758	47,916
Internal expense transfer									99,851	53,050	56,575
Income (loss) before income taxes									110,055	64,331	65,054
Return on average interest earning assets (pre-tax)	1.77%				1.94%				1.77%	1.94%	1.72%
Commercial Lending [Member]
Average interest earning assets	3,394,161				6,153,870				3,394,161	6,153,870	5,930,220
Interest income									171,939	355,565	340,358
Interest expense									47,832	94,944	111,235
Net interest income (loss)									124,107	260,621	229,123
Provision for credit losses									6,806	34,858	26,816
Net interest income (loss) after provision for credit losses									117,301	225,763	202,307
Non-interest income									45,830	7,927	7,465
Non-interest expense									56,884	42,131	40,190
Internal expense transfer									55,059	97,704	88,043
Income (loss) before income taxes									51,188	93,855	81,539
Return on average interest earning assets (pre-tax)	1.51%				1.53%				1.51%	1.53%	1.37%
Investment Management [Member]
Average interest earning assets	3,205,756				3,204,762				3,205,756	3,204,762	3,325,737
Interest income									132,530	146,851	162,834
Interest expense									45,176	49,445	62,382
Net interest income (loss)									87,354	97,406	100,452
Net interest income (loss) after provision for credit losses									87,354	97,406	100,452
Non-interest income									7,381	6,166	5,699
Non-interest expense									1,016	992	675
Internal expense transfer									51,644	51,258	50,102
Income (loss) before income taxes									42,075	51,322	55,374
Return on average interest earning assets (pre-tax)	1.31%				1.60%				1.31%	1.60%	1.67%
Corporate And Other Adjustments [Member]
Interest income									(6,518)	(6,036)	(4,318)
Interest expense									18,431	18,431	18,431
Net interest income (loss)									(24,949)	(24,467)	(22,749)
Net interest income (loss) after provision for credit losses									(24,949)	(24,467)	(22,749)
Non-interest income									42,121	24,689	10,854
Non-interest expense									229,859	224,801	217,247
Internal expense transfer									(206,554)	(202,012)	(194,720)
Income (loss) before income taxes									$ (6,133)	$ (22,567)	$ (34,422)
Return on average interest earning assets (pre-tax)	0.00%				0.00%				0.00%	0.00%	0.00%