Details Of Certain Accounts - Accrued Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Accrued payroll and related benefits	$ 12,766	$ 14,775
Current asset retirement obligations	553	553
Unearned revenue	11,557	12,841
Billing in excess of cost	826	0
Accrued interest	1,940	4,854
Derivative liability (Note 14)	20,164	23,192
Taxes payable excluding income tax payable	10,719	8,136
Other	8,740	7,290
Total accrued liabilities	$ 67,265	$ 71,641