Parent Company Information (Components of Condensed Income Statement The Parent Company) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Operating Income:
Interest on securities and interest-bearing deposits									$ 172,151	$ 178,215	$ 182,599
Interest on loan									490,985	485,666	486,883
Provision for loan losses	(9,000)	(8,500)	(8,500)	(7,500)	(7,500)	(5,000)	(5,000)	(4,000)	(33,500)	(21,500)	(22,500)
Net gain on sale of investment securities	4	269	333	106	0	810	2,537	0	712	3,347	3,823
Alternative investments (loss) income									(389)	(720)	1,605
Other non-interest income	44,260	45,988	51,918	48,172	52,940	47,669	44,816	43,986
Operating Expense:
Loss on swap termination									438	48	1,815
Other non-interest expense									73,037	69,018	87,091
Income tax benefit	(18,755)	(18,158)	(20,835)	(18,922)	(20,261)	(19,489)	(18,312)	(16,603)	(76,670)	(74,665)	(57,951)
Income from continuing operations before income tax expense	62,509	65,463	67,208	61,039	68,787	64,482	59,552	55,541	256,219	248,362	207,334
Income from continuing operations									179,549	173,697	149,383
Income from discontinued operations, net of tax									0	0	1,995
Parent Company [Member]
Operating Income:
Dividend income from bank subsidiary									90,000	140,000	170,000
Interest on securities and interest-bearing deposits									1,025	634	562
Interest on loan									0	0	810
Provision for loan losses									0	0	136
Net loss on trading securities									0	0	(1,799)
Net gain on sale of investment securities									1,273	409	374
Alternative investments (loss) income									(392)	(720)	1,605
Other non-interest income									152	157	149
Total operating income									92,058	140,480	171,837
Operating Expense:
Interest expense on borrowings									7,273	13,186	18,651
Loss on swap termination									0	0	16,223
Compensation and benefits									10,787	10,245	9,121
Other non-interest expense									5,966	5,746	5,766
Total operating expense									24,026	29,177	49,761
Income before income tax benefit and equity in undistributed earnings of subsidiaries and associated companies									68,032	111,303	122,076
Income tax benefit									9,742	10,107	18,481
Equity in undistributed earnings of subsidiaries and associated companies									101,775	52,287	8,827
Income from continuing operations									179,549	173,697	149,384
Income from discontinued operations, net of tax									0	0	1,995
Net income									$ 179,549	$ 173,697	$ 151,379