Net Periodic Pension Cost (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Components of the net periodic pension cost:
Interest cost	$ 554	$ 736	$ 971
Expected return on plan assets	(1,120)	(1,340)	(1,671)
Amortization of actuarial losses	928	686	957
Amortization of prior service cost	31	29	29
Net periodic pension cost	$ 393	$ 111	$ 286