Benefit Plans - Change in Plan Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Pension and Supplemental Executive Retirement Plans
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair Value of Plan Assets at Beginning of Year	$ 411,245	$ 402,691
Company Contributions	7,162	12,453
Plan Participants' Contributions	0	0
Benefit Payments from the Fund	(40,482)	(40,260)
Benefit Payments paid directly by Company	(362)	(5,953)
Actual Return on Assets	13,992	42,314
Other Adjustments	0	0
Fair Value of Plan Assets at End of Year	391,555	411,245
Other Postretirement Benefit Plan
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair Value of Plan Assets at Beginning of Year	119,024	99,590
Company Contributions	0	0
Plan Participants' Contributions	456	425
Benefit Payments from the Fund	(1,963)	(1,975)
Benefit Payments paid directly by Company	0	0
Actual Return on Assets	23,773	21,409
Other Adjustments	(451)	(425)
Fair Value of Plan Assets at End of Year	$ 140,839	$ 119,024