Other Liabilities (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($) item	Dec. 31, 2015 USD ($)
Other Liabilities
Interest rate swap contracts, Current	$ 16,533	$ 23,327
Deferred revenue, Current	249	2,313
Asset retirement obligations	9,821	3,042
Other, Current	1,634	4,050
Total, Current	28,237	32,732
Interest rate swap contracts, Noncurrent	14,456	21,872
Deferred revenue, Noncurrent	1,698	1,217
Other, Noncurrent	2,537	7,568
Total, Noncurrent	$ 18,691	$ 30,657
Derivatives, Number Reclassified | item	2