Fair Value Measurements - Assets and Liabilities Measured at Fair Value (Details) - USD ($) $ in Thousands		Sep. 30, 2017	Dec. 31, 2016
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Current derivative asset		$ 4,153	$ 0
Long-term derivative asset	[1]	16
Total derivative instruments		4,169
Current derivative liability	[2]	22
Long-term derivative liability	[3]	15
Total derivative instruments		37
Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Current derivative asset		4,153
Long-term derivative asset	[1]	16
Total derivative instruments		4,169
Current derivative liability	[2]	22
Long-term derivative liability	[3]	15
Total derivative instruments		$ 37

[1] Included in other assets in the Consolidated Balance Sheet

[2] Included in accrued liabilities in the Consolidated Balance Sheet

[3] Included in other long-term obligations in the Consolidated Balance Sheet