Summary of Significant Accounting Policies (Details Textual) - USD ($) $ in Thousands	6 Months Ended		12 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Summary of Significant Accounting Policies [Line Items]
Restricted cash	$ 3,700		$ 5,000
Proceeds from sale/maturity of short-term investments	61,833	$ 94,794
Increase in non-current deferred income tax assets	12,025		17,462
Decrease in non-current deferred income tax liabilities	$ (50)		(182)
Reclassification of Debt Issuance Costs From Other Assets to Long Term Debt | ASU 2015-03
Summary of Significant Accounting Policies [Line Items]
Deferred issuance costs			5,400
Reclassification of Deferred Tax Assets Liabilities From Current to Non-Current | ASU 2015-17
Summary of Significant Accounting Policies [Line Items]
Decrease in current deferred income tax assets			(18,100)
Increase in non-current deferred income tax assets			9,100
Decrease in non-current deferred income tax liabilities			$ (9,000)
Maximum
Summary of Significant Accounting Policies [Line Items]
Short-term investment contractual maturities	2 years		2 years