Employee Benefit Plans - Reconciliation of Benefit Obligations, Plan Assets and Funded Status (Details) - Other postretirement benefits - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Change in benefit obligation:
Benefit obligation at beginning of year	$ 6,145	$ 6,075
Service cost	104	103	$ 103
Interest cost	99	154	210
Actuarial (gain) loss	(504)	202
Plan participants' contributions	603	474
Benefits paid	(903)	(863)
Benefit obligation, end of year	$ 5,544	$ 6,145	$ 6,075