EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Income (Numerator)
Income available to common stockholders (in dollars)	$ 43,863	$ 45,171
Shares (Denominator)
Basic (in shares)	62,722	62,292
Total average equivalent shares	65,063	64,494
Per Share Amount
Net income per share, basic (in dollars per share)	$ 0.70	$ 0.73
Net income per share, diluted (in dollars per share)	$ 0.67	$ 0.70
Stock options
Shares (Denominator)
Effect of dilutive stock based compensation (in shares)	2,299	2,182
Restricted stock units
Shares (Denominator)
Effect of dilutive stock based compensation (in shares)	42	20