EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Earning per share
Authorized common stock (in shares)	199,000				199,000				199,000	199,000
Common stock, par value (in dollars per share)	$ 0.01				$ 0.01				$ 0.01	$ 0.01
Income (Numerator)
Income available to common stockholders, basic (in dollars)	$ 48,533	$ 56,750	$ 73,915	$ 63,004	$ 40,674	$ 38,996	$ 55,775	$ 59,300	$ 242,202	$ 194,745	$ 220,030
Income available to common stockholders, diluted (in dollars)									$ 242,202	$ 194,745	$ 220,030
Shares (Denominator)
Basic (in shares)	63,835	64,010	63,471	62,964	62,834	62,378	62,402	62,128	63,574	62,437	62,435
Total average equivalent shares	66,192	66,702	66,232	65,349	65,344	65,129	64,850	64,414	66,150	64,958	64,596
Per Share Amount
Net income per share, basic (in dollars per share)	$ 0.76	$ 0.89	$ 1.16	$ 1.00	$ 0.65	$ 0.63	$ 0.89	$ 0.95	$ 3.81	$ 3.12	$ 3.52
Net income per share, diluted (in dollars per share)	$ 0.73	$ 0.85	$ 1.12	$ 0.96	$ 0.62	$ 0.60	$ 0.86	$ 0.92	$ 3.66	$ 3.00	$ 3.41
Stock options
Shares (Denominator)
Effect of dilutive stock based compensation (in shares)									2,344	2,440	2,106
Restricted stock units
Shares (Denominator)
Effect of dilutive stock based compensation (in shares)									232	81	55