Details Of Certain Accounts - Accrued Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Accrued payroll and related benefits	$ 26,093	$ 30,685
Deferred revenue (Note 9)	11,640	12,609
Derivative liability (Note 15)	9,057	10,625
Other	17,606	17,761
Total accrued liabilities	$ 64,396	$ 71,680