Fair Value Measurements (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016
Long-term Debt			$ 207,804
Fair Value, Measurements, Recurring | Level 2 | Carrying Amount
Long-term Debt	$ 294,501,000	$ 293,797,000
Other long-term debt and capital lease obligation	48,622,000	56,998,000
Total long-term debit and capital obligations	343,123,000	350,795,000
Fair Value, Measurements, Recurring | Level 2 | Fair Value
Long-term Debt	314,361,000	306,547,000
Other long-term debt and capital lease obligation	48,622,000	56,998,000
Total long-term debit and capital obligations	$ 362,983,000	$ 363,545,000