Employee Benefit Plans - Other Compensation Plans (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Classification of liabilities in the Consolidated Balance Sheets
Current liabilities	$ 902	$ 857
Total liabilities	3,959	3,909
Plan expenses	800	700	$ 700
Accrued compensation
Classification of liabilities in the Consolidated Balance Sheets
Current liabilities	902	857
Other long-term liabilities
Classification of liabilities in the Consolidated Balance Sheets
Long-term liabilities	$ 3,057	$ 3,052