Condensed Financial Information - Parent Company Only Income statement (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Condensed Financial Statements, Captions [Line Items]
Total Other Income	$ 216,624	$ 187,727	$ 182,320
Income Before Income Taxes	217,446	196,411	172,741
Income Tax Expense (Benefit)	57,601	50,838	44,409
Net Income	159,845	145,573	128,332
Preferred Stock dividends and discount accretion	0	0	(16,303)
Net Income Available to Common Shareholders	159,845	145,573	112,029
Parent [Member]
Condensed Financial Statements, Captions [Line Items]
Dividends from subsidiaries	142,000	91,325	63,850
Other	88,380	78,662	73,438
Total Other Income	230,380	169,987	137,288
Expenses	124,525	112,398	105,012
Income Before Income Taxes	105,855	57,589	32,276
Income Tax Expense (Benefit)	(10,847)	(11,523)	(11,180)
Income (Loss) from Continuing Operations Attributable to Parent	116,702	69,112	43,456
Bank subsidiaries	46,350	80,908	78,146
Non-bank subsidiaries	(3,207)	(4,447)	6,730
Net Income	159,845	145,573	128,332
Preferred Stock dividends and discount accretion	0	0	(16,303)
Net Income Available to Common Shareholders	$ 159,845	$ 145,573	$ 112,029