Employee Benefit Plans - Recognized Net Periodic Benefit Cost and Other Comprehensive Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Retirement Benefits [Abstract]
Service cost	$ 61	$ 74	$ 87
Interest cost	51	89	83
Net amortization of transition obligation and actuarial loss	0	23	84
Net periodic benefit cost	112	186	254
Net gain	(277)	(518)	(404)
Amortization	0	(23)	(84)
Total recognized in other comprehensive income	(277)	(541)	(488)
Total recognized in net periodic benefit cost and other comprehensive income	$ (165)	$ (355)	$ (234)