STOCKHOLDERS' EQUITY (Details 2) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
STOCKHOLDERS' EQUITY
Common stock, shares outstanding	137,705,407		137,705,407		140,294,092
Earnings per share calculations
Net income	$ 74,015	$ 70,557	$ 146,106	$ 138,640
Less: Preferred stock dividends	(1,714)	(1,714)	(3,428)	(3,428)
Less: Earnings allocated to participating securities	(400)	(859)	(988)	(1,718)
Basic EPS - income allocated to common stockholders	71,901	67,984	141,690	133,494
Effect of dilutive securities:
Restricted stock units	33	7	68	15
Convertible preferred stock		1,714	3,428	3,428
Diluted EPS - income allocated to common stockholders	$ 71,934	$ 69,705	$ 145,186	$ 136,937
Number of Shares
Weighted average shares outstanding	137,536,000	142,107,000	137,592,000	143,727,000
Effect of dilutive securities on weighted average shares outstanding
Stock options (in shares)	59,000	36,000	55,000	41,000
Restricted stock units (in shares)	221,000	72,000	227,000	75,000
Convertible preferred stock (in shares)		5,571,000	3,699,000	5,571,000
Total weighted average diluted shares outstanding	137,816,000	147,786,000	141,573,000	149,414,000
Per Share Amounts
Basic EPS - income allocated to common stockholders (in dollars per share)	$ 0.52	$ 0.48	$ 1.03	$ 0.93
Diluted EPS - Income available to common stockholders (in dollars per share)	$ 0.52	$ 0.47	$ 1.03	$ 0.92