Pension and Other Postretirement Benefits - Components of Net Periodic Benefit Costs (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Pension Benefits
Components of net periodic benefit cost:
Service cost	$ 3,953	$ 3,930	$ 3,668
Interest cost	7,512	9,729	12,261
Expected return on plan assets	(16,337)	(16,357)	(15,699)
Amortization of prior service cost	110	190	169
Settlement loss (gain)	(18)	3,153	(7)
Other adjustments	(191)	0	0
Net loss (gain) recognition	3,764	2,930	1,432
Net periodic benefit cost (income)	(1,207)	3,575	1,824
Other Benefits
Components of net periodic benefit cost:
Service cost	33	33	35
Interest cost	727	809	960
Expected return on plan assets	0	0	0
Amortization of prior service cost	0	0	0
Settlement loss (gain)	0	0	0
Other adjustments	0	0	0
Net loss (gain) recognition	(43)	(59)	(133)
Net periodic benefit cost (income)	$ 717	$ 783	$ 862