EARNINGS PER SHARE (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
EARNINGS PER SHARE
Authorized common stock (in shares)	199,000,000		199,000,000		199,000,000
Common stock, par value (in dollars per share)	$ 0.01		$ 0.01		$ 0.01
Diluted
Income available to common shareholders (in dollars)	$ 45,264	$ 42,127	$ 135,095	$ 127,622
Shares of common stock	66,092,000	66,541,000	66,222,000	66,439,000
Total average equivalent shares	67,986,000	68,353,000	68,273,000	68,711,000
Net income per share, diluted (in dollars per share)	$ 0.67	$ 0.62	$ 1.98	$ 1.86
Basic
Income available to common shareholders (in dollars)	$ 45,264	$ 42,127	$ 135,095	$ 127,622
Shares of common stock	66,092,000	66,541,000	66,222,000	66,439,000
Net income per share, basic (in dollars per share)	$ 0.68	$ 0.63	$ 2.04	$ 1.92
Stock options
Diluted
Effect of dilutive stock based compensation (in shares)	1,887,000	1,804,000	2,041,000	2,259,000
Restricted stock
Diluted
Effect of dilutive stock based compensation (in shares)	7,000	8,000	10,000	13,000