Consolidated Balance Sheets Parenthetical (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Common Stock, No Par Value	$ 0	$ 0
Common Stock, Shares Authorized	300,000,000	300,000,000
Common Stock, Shares, Issued	115,121,731	115,121,731
Preferred Stock, No Par Value	$ 0	$ 0
Preferred Stock, Shares Authorized	7,000,000	7,000,000
Preferred Stock, Shares Subscribed but Unissued	7,000,000	7,000,000
Treasury Stock, Shares	5,472,915	5,870,923
Expected Reimbursement for Losses Incurred Covered Other Real Estate	$ 49,000	$ 1,311,000
Covered Loans Loss Share Receivable	$ 113,734,000	$ 205,664,000
Series A Preferred Stock [Member]
Preferred Stock, No Par Value	$ 0	$ 0
Preferred Stock, Shares Outstanding	0	0
Preferred Stock, Shares Authorized	800,000	800,000
Series B Preferred Stock [Member]
Preferred Stock, No Par Value	$ 0	$ 0
Preferred Stock, Shares Outstanding	0	0
Preferred Stock, Shares Authorized	220,000	220,000