Retirement Plans - Net Periodic Pension Cost - Pension Plan (Details) - Pension plan - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Cost components:
Service cost	$ 0	$ 0	$ 0
Interest cost	(291)	(338)	(389)
Expected return on plan assets	752	643	522
Net amortization and deferral	(74)	(68)	(75)
Total net periodic pension earnings/(cost)	$ 387	$ 237	$ 58