EARNINGS PER SHARE (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
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 stockholders (in dollars)	$ 48,595	$ 45,264	$ 150,060	$ 135,095
Shares of common stock	64,886,000	66,092,000	65,225,000	66,222,000
Total average equivalent shares	66,845,000	67,986,000	67,761,000	68,273,000
Net income per share, diluted (in dollars per share)	$ 0.73	$ 0.67	$ 2.21	$ 1.98
Basic
Income available to common stockholders (in dollars)	$ 48,595	$ 45,264	$ 150,060	$ 135,095
Shares of common stock	64,886,000	66,092,000	65,225,000	66,222,000
Net income per share, basic (in dollars per share)	$ 0.75	$ 0.68	$ 2.30	$ 2.04
Stock options
Diluted
Effect of dilutive stock based compensation (in shares)	1,953,000	1,887,000	2,505,000	2,041,000
Restricted stock units
Diluted
Effect of dilutive stock based compensation (in shares)	6,000	7,000	31,000	10,000