Employee Benefit Plans - Accumulated Post-Retirement Benefit Obligation, Funded Status, and Net Periodic Benefit Cost (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Change in Benefit Obligations [Roll Forward]
Benefit obligation at beginning of year	$ 1,599	$ 1,874	$ 1,870
Interest cost	66	77	77
Benefits paid	(97)	(117)	(113)
Actuarial (gain) loss				$ 13	$ (235)	$ 40
Benefit obligation at end of period	1,581	1,599	1,874
Funded Status of Plan [Abstract]
Benefit obligation at end of period	(1,599)	(1,874)	(1,874)	(1,581)	(1,599)	(1,874)
Unamortized (gain) loss				(31)	(47)	186
Accrued benefit cost				$ (1,612)	$ (1,646)	$ (1,688)
Weighted average discount rate as of December 31				0.0300	0.0425	0.0425
Components of Net Periodic Benefit Cost [Abstract]
Interest cost	66	77	77
Amortization of loss	0	0	0
Other settlement (income) expense	(2)	(3)	11
Net periodic benefit cost	$ 64	$ 74	$ 88
Weighted average discount rate for net periodic cost	3.00%	4.25%	4.25%