Employee Benefit Plans - Fair Value of Plan Asset Allocation (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Total pension plan assets	$ 6,580	$ 6,391	$ 7,474
Equity securities
Defined Benefit Plan Disclosure [Line Items]
Total pension plan assets	0	0
Debt securities
Defined Benefit Plan Disclosure [Line Items]
Total pension plan assets	0	0
Other securities
Defined Benefit Plan Disclosure [Line Items]
Total pension plan assets	$ 6,580	$ 6,391