STOCKHOLDERS' EQUITY (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended		1 Months Ended		3 Months Ended	6 Months Ended		1 Months Ended		3 Months Ended	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Apr. 30, 2012 Series A Non-Cumulative Perpetual Convertible Preferred Stock	Apr. 30, 2008 Series A Non-Cumulative Perpetual Convertible Preferred Stock	Jun. 30, 2012 Series A Non-Cumulative Perpetual Convertible Preferred Stock	Jun. 30, 2012 Series A Non-Cumulative Perpetual Convertible Preferred Stock	Apr. 23, 2008 Series A Non-Cumulative Perpetual Convertible Preferred Stock	Apr. 30, 2012 Common Stock	Jan. 31, 2012 Common Stock	Jun. 30, 2012 Common Stock	Jun. 30, 2012 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 (in shares)						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	85,710
Amount of stock repurchase approved by the Board of Directors											200.0
Quarterly Dividends
Dividend per share (in dollars per share)					$ 20.00
Dividend per share (in dollars per share)	$ 0.10	$ 0.05	$ 0.20	$ 0.06						$ 0.10
Common stock cash dividends paid												14.5	29.3
Preferred stock cash dividends paid							$ 1.7	$ 3.4
Purchase of treasury stock pursuant to the Stock Repurchase Program, shares			6,784,227
Weighted average cost of shares repurchased (in dollars per share)			$ 22.08