DEBT (Components of Interest Expense) (Details) - 2016 Convertible Senior Notes - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Debt Instrument [Line Items]
Amortization of the discount on the liability component	$ 7,917	$ 7,104	$ 6,463
Cash interest related to the contractual interest coupon	3,430	3,342	3,218
Total	11,347	10,446	9,681
Amortization of debt discount, capitalized interest	600	900	1,000
Cash interest related to contractual interest coupon, capitalized interest	$ 300	$ 400	$ 500