INVESTMENT SECURITIES (Details 3) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
INVESTMENT SECURITIES
Gross gains on sale of investment securities	$ 28,200,000	$ 18,100,000	$ 33,500,000
Gross losses on sale of investment securities	27,400,000	8,400,000	2,300,000
Net income statement impact of gain on sale of investment securities	757,000	9,700,000	31,200,000
Net proceeds for sales of investment securities	1,230,000,000	702,600,000	1,340,000,000
Tax expense on the sale of investment securities	$ 318,000	$ 4,100,000	$ 13,100,000