STOCKHOLDERS' EQUITY (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended		1 Months Ended		3 Months Ended		0 Months Ended	1 Months Ended	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Jan. 31, 2013 Series A Non-Cumulative Perpetual Convertible Preferred Stock	Apr. 30, 2008 Series A Non-Cumulative Perpetual Convertible Preferred Stock	Mar. 31, 2013 Series A Non-Cumulative Perpetual Convertible Preferred Stock	Apr. 23, 2008 Series A Non-Cumulative Perpetual Convertible Preferred Stock	Jan. 23, 2013 Common Stock	Jan. 31, 2013 Common Stock	Mar. 31, 2013 Common Stock
Class of Stock
Number of shares issued during the period				200,000
Preferred stock dividend rate (as a percent)				8.00%
Preferred stock liquidation preference (in dollars per share)				$ 1,000
Proceeds from issuance of convertible preferred stock				$ 194.1
Number of common stock shares convertible from each share of convertible preferred stock				64.9942
Convertible preferred stock conversion price per share				$ 15.39
Conversion premium of the convertible preferred stock based on the closing price of the common stock (as a percent)				22.50%
Closing price of common stock at issuance of convertible preferred stock (in dollars per share)						$ 12.56
Preferred shares outstanding					85,710
Amount of stock repurchase approved by the Board of Directors							200.0
Purchase of treasury stock pursuant to the Stock Repurchase Program, shares	3,543,100	4,554,827
Weighted average price of shares repurchased (in dollars per share)	$ 24.53	$ 22.14
Total cost of repurchase of treasury shares	87.0	101.0
Quarterly Dividends
Dividend per share (in dollars per share)			$ 20.00
Preferred stock cash dividends paid					1.7
Dividend per share (in dollars per share)	$ 0.15	$ 0.10						$ 0.15
Common stock cash dividends paid									$ 21.1