Other Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Other Liabilities
Interest rate swap contracts, Current	$ 9,252	$ 16,533
Asset retirement obligations	10,535	9,821
Deferred revenue, Current	144	249
Other, Current	11,609	1,634
Total current portion of other long-term liabilities	31,540	28,237
Acquisition-related contingent consideration	42,434
Interest rate swap contracts, Noncurrent	9,449	14,456
Deferred revenue, Noncurrent	1,839	1,698
Other, Noncurrent	18,039	2,537
Total other long-term liabilities	$ 71,761	$ 18,691