INDEBTEDNESS (Details Textual) $ / shares in Units, $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2015 USD ($)	Sep. 30, 2015 USD ($)	Dec. 31, 2014 USD ($) $ / shares shares
Long-term Debt, Gross	$ 143,750	$ 143,750
Debt Instrument, Unamortized Discount	28,557	28,557
Amortization of Financing Costs	$ 211	$ 633
Convertible Senior Notes [Member]
Long-term Debt, Gross			$ 143,800
Proceeds from Issuance of Debt			$ 122,600
Long-term Debt, Percentage Bearing Fixed Interest, Percentage Rate			3.00%
Underlying Shares Of Common Stock Convertible Debt | shares			2,068,793
Debt Instrument, Convertible, Conversion Price | $ / shares			$ 69.48
Debt Instrument, Convertible, Threshold Trading Days			20
Debt Instrument Percent Of Conversion Price			130.00%
Per Note Principal | $ / shares			$ 1,000
Debt Instrument, Unamortized Discount			$ 33,600
Deferred Offering Costs			$ 5,500
Exercise Price Of Bond Hedge | $ / shares			$ 69.48
Underlying Shares Of Common Stock Bond Hedge | shares			2,068,792
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares			$ 96.21
Net Adjustments To Additional Paid In Capital Bond Hedge Acquired Warrant Issued Net			$ 15,600
Debt Instrument, Interest Rate, Effective Percentage	7.70%	7.70%
Debt Instrument, Convertible, Threshold Consecutive Trading Days			30 days
Amortization of Financing Costs			$ 4,200
Payments of Stock Issuance Costs			$ 1,300