Parent Company Information (Components of Condensed Cash Flow The Parent Company) (Details) (USD $) In Thousands, unless otherwise specified	0 Months Ended	12 Months Ended
	Jun. 08, 2011	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Operating activities:
Income from continuing operations		$ 179,549	$ 173,697	$ 149,383
Adjustments to reconcile income from continuing operations to net cash provided by operating activities:
Stock-based compensation		10,664	8,955	6,040
Excess tax benefits from stock-based compensation		(389)	(812)	(392)
Net cash provided by operating activities		476,724	257,082	266,130
Investing activities:
Increase in interest-bearing deposits		31,761	(2,143)	(43,251)
Purchases of available for sale securities		(952,995)	(1,204,079)	(1,305,583)
Proceeds from maturities and principal payments of available for sale securities		741,467	854,747	545,933
Proceeds from sale of available for sale securities		57,804	148,222	278,757
Net decrease in loan		(742,055)	(915,435)	(338,037)
Net cash used for investing activities		(1,150,131)	(1,390,092)	(771,709)
Financing activities:
Repayment of long-term debt		(102,579)	(210,971)	(22,689)
Issuance of preferred stock		0	122,710	0
Cash dividends paid to common shareholders		(48,952)	(30,667)	(13,978)
Cash dividends paid to preferred shareholders		(10,803)	(2,460)	(2,460)
Exercise of stock options		2,736	996	213
Excess tax benefits from stock-based compensation		389	812	392
Common stock issued		731	560	689
Common stock repurchased		(672)	(53,243)	(1,670)
Common stock warrants repurchased	(14,400)	(30)	(388)	(16,285)
Net cash provided by financing activities		644,740	1,189,336	539,692
Discontinued Operations:
Operating activities		0	0	1,995
Net cash provided by discontinued operations		0	0	1,995
Increase (decrease) in cash and due from banks		(28,667)	56,326	36,108
Cash and due from banks at beginning of year		252,283	195,957	159,849
Cash and due from banks at end of year		223,616	252,283	195,957
Parent Company [Member]
Operating activities:
Net income		179,549	173,697	151,379
Income from discontinued operations, net of tax		0	0	1,995
Income from continuing operations		179,549	173,697	149,384
Adjustments to reconcile income from continuing operations to net cash provided by operating activities:
Equity in undistributed earnings of subsidiaries and associated companies		(101,775)	(52,287)	(8,827)
Stock-based compensation		10,664	8,955	6,040
Excess tax benefits from stock-based compensation		(389)	(812)	(392)
Other, net		(1,545)	(6,610)	21,285
Net cash provided by operating activities		86,504	122,943	167,490
Investing activities:
Increase in interest-bearing deposits		(41,011)	(24,081)	(120,133)
Purchases of available for sale securities		(75)	(8,272)	(3,714)
Proceeds from maturities and principal payments of available for sale securities		0	775	575
Proceeds from sale of available for sale securities		13,544	1,073	2,353
Net decrease in loan		0	0	13,000
Net cash used for investing activities		(27,542)	(30,505)	(107,919)
Financing activities:
Repayment of long-term debt		0	(136,070)	(22,689)
Issuance of preferred stock		0	122,710	0
Cash dividends paid to common shareholders		(48,952)	(30,667)	(13,978)
Cash dividends paid to preferred shareholders		(10,803)	(2,460)	(2,460)
Exercise of stock options		2,736	996	213
Excess tax benefits from stock-based compensation		389	812	392
Common stock issued		731	560	689
Common stock repurchased		(672)	(53,243)	(1,670)
Common stock warrants repurchased		(30)	(388)	(16,285)
Net cash provided by financing activities		(56,601)	(97,750)	(55,788)
Discontinued Operations:
Operating activities		0	0	1,995
Net cash provided by discontinued operations		0	0	1,995
Increase (decrease) in cash and due from banks		2,361	(5,312)	5,778
Cash and due from banks at beginning of year		10,091	15,403	9,625
Cash and due from banks at end of year		$ 12,452	$ 10,091	$ 15,403