Condensed Parent Company Financial Statements (Statements Of Income) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Income
Gains on available-for-sale securities, net	$ 2,561	$ 409	$ 1,109	$ 816	$ 309	$ 225	$ 1,152	$ 106	$ 4,895	$ 1,792	$ 9,832
Expenses
Interest expense	23,867	25,626	27,421	30,591	32,970	36,541	36,739	38,166	107,505	144,416	177,271
Salaries and employee benefits									288,589	237,785	215,766
Income before taxes	48,871	52,173	41,329	37,759	31,974	50,046	18,965	27,048	180,132	128,033	100,807
Income tax benefit	(18,782)	(19,871)	(15,734)	(14,549)	(12,753)	(19,844)	(7,215)	(10,646)	(68,936)	(50,458)	(37,478)
Net income	30,089	32,302	25,595	23,210	19,221	30,202	11,750	16,402	111,196	77,575	63,329
Parent Company [Member]
Income
Dividends and interest from subsidiaries									47,295	30,783	15,592
Trading revenue									0	0	4,839
Gains on available-for-sale securities, net									64	164	57
Other income									605	(487)	1,421
Total income									47,964	30,460	21,909
Expenses
Interest expense									16,840	21,342	18,667
Salaries and employee benefits									20,042	12,435	8,975
Other expenses									27,428	14,037	10,838
Total expenses									64,310	47,814	38,480
Income before taxes									(16,346)	(17,354)	(16,571)
Income tax benefit									23,127	16,573	8,997
(Loss) income before equity in undistributed net loss of subsidiaries									6,781	(781)	(7,574)
Equity in undistributed net income (loss) of subsidiaries									104,415	78,356	70,903
Net income									$ 111,196	$ 77,575	$ 63,329