Employee Benefit Plans - Other Compensation Plans (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Classification of liabilities in the Consolidated Balance Sheets
Current liabilities	$ 1,040	$ 973
Other long-term liabilities	3,753	3,327
Total liabilities	4,793	4,300
Plan expenses	1,200	1,300	$ 1,000
Accrued compensation
Classification of liabilities in the Consolidated Balance Sheets
Current liabilities	$ 1,040	$ 973