SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Revision of Prior Period Financial Statements) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Capital in excess of par value	$ 495,462	$ 498,702	$ 488,292	$ 426,884
Treasury stock	(270,052)	(1,026,117)	(738,558)	(622,075)
Stock option exercises & restricted stock vestings	84,568	63,377	63,751
Total Stockholders' Equity	$ 1,149,706	1,103,916	1,480,308	1,380,498
Stock option exercises & restricted stock vestings
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Capital in excess of par value		60,410	61,408
Treasury stock		2,958	2,330
Total Stockholders' Equity		63,377	63,751
As Previously Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Capital in excess of par value		507,313	493,947	430,210
Treasury stock		(1,034,728)	(744,213)	(625,401)
Total Stockholders' Equity		1,103,916	1,480,308	1,380,498
As Previously Reported | Stock option exercises & restricted stock vestings
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Capital in excess of par value		63,366	63,737
Treasury stock		2	1
Total Stockholders' Equity		63,377	63,751
Reissuance of incorrectly accounted treasury shares | Adjustment
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Capital in excess of par value		(8,611)	(5,655)	(3,326)
Treasury stock		8,611	5,655	$ 3,326
Reissuance of incorrectly accounted treasury shares | Adjustment | Stock option exercises & restricted stock vestings
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Capital in excess of par value		(2,956)	(2,329)
Treasury stock		$ 2,956	$ 2,329