Commitments and Contingencies - Other Installment Contracts (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Long-term Purchase Commitment [Line Items]
Current reflected in other current liabilities	$ 2,157	$ 1,849
Other Installment Contracts
Long-term Purchase Commitment [Line Items]
2017	2,797
2018	1,264
2019	1,231
2020	1,018
2021	981
Thereafter	7,103
Total	14,394
Less amounts representing interest	(3,545)
Present value	10,849
Current reflected in other current liabilities	2,157
Noncurrent reflected in other liabilities	$ 8,692