EARNINGS PER SHARE (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
EARNINGS PER SHARE
Authorized common stock (in shares)	199,000,000		199,000,000
Common stock, par value (in dollars per share)	$ 0.01		$ 0.01
Diluted
Income available to common shareholders (in dollars)	$ 48,389	$ 40,029
Shares of common stock	65,468,000	66,155,000
Total average equivalent shares	68,232,000	68,296,000
Net income per share, diluted (in dollars per share)	$ 0.71	$ 0.59
Basic
Income available to common shareholders (in dollars)	$ 48,389	$ 40,029
Shares of common stock	65,468,000	66,155,000
Net income per share, basic (in dollars per share)	$ 0.74	$ 0.61
Stock options
Diluted
Effect of dilutive stock based compensation (in shares)	2,738,000	2,133,000
Restricted stock
Diluted
Effect of dilutive stock based compensation (in shares)	26,000	8,000