Employee Benefits (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Pension Plan
Net periodic benefit cost
Service cost	$ 1,120	$ 3,020
Interest cost	1,933	1,728
Expected return on plan assets	(4,723)	(4,202)
Amortization of prior service credit	(820)	(809)
Amortization of net loss	194	999
Special event plan closure	0	0
Net periodic benefit cost	(2,296)	736
Estimated 2021 pension plan contribution, disclosed in prior year 10K			$ 4,000
Contribution by employer	1,000
Postretirement Benefit Plan
Net periodic benefit cost
Service cost	0	148
Interest cost	1	69
Expected return on plan assets	0	0
Amortization of prior service credit	(3,771)	(3,196)
Amortization of net loss	706	492
Special event plan closure	0	(20,177)
Net periodic benefit cost	$ (3,064)	$ (22,664)