Employee Postretirement Benefits - Reconciliation of Changes in Fair Value of Plan Assets and Plan's Benefit Obligations (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Change in Fair Value of Plan Assets:
Fair Value of Plan Assets, beginning balance	$ 387,212
Fair Value of Plan Assets, ending balance	313,798	$ 387,212
Pension Benefits (Pension Plan)
Change in Fair Value of Plan Assets:
Fair Value of Plan Assets, beginning balance	387,212	360,678
Actual Return on Plan Assets	(76,485)	32,816
Company Contributions	20,000	10,000
Benefit Payments	(16,930)	(16,282)
Participant Premium Payments	0	0
Fair Value of Plan Assets, ending balance	313,797	387,212	$ 360,678
Change in Benefit Obligation:
Projected Benefit Obligation, beginning balance	416,697	428,396
Service Cost	6,576	7,462	6,621
Interest Cost	12,344	11,660	13,053
Benefit Payments	(16,930)	(16,282)
Participant Premium Payments	0	0
Plan Amendments	0	0
Actuarial Loss	(110,632)	(14,539)
Projected Benefit Obligation, ending balance	308,055	416,697	428,396
Funded Status	5,742	(29,485)
Amounts Recognized in Consolidated Balance Sheet at December 31:
Noncurrent Assets	5,742	0
Current Liabilities	0	0
Noncurrent Liabilities and Deferred Credits	0	(29,485)
Net Asset (Liability)	5,742	(29,485)
Pension Benefits (ESSRP)
Change in Fair Value of Plan Assets:
Fair Value of Plan Assets, beginning balance	0	0
Actual Return on Plan Assets	0	0
Company Contributions	2,205	1,562
Benefit Payments	(2,205)	(1,562)
Participant Premium Payments	0	0
Fair Value of Plan Assets, ending balance	0	0	0
Change in Benefit Obligation:
Projected Benefit Obligation, beginning balance	46,840	47,894
Service Cost	195	187	179
Interest Cost	1,341	1,228	1,449
Benefit Payments	(2,205)	(1,562)
Participant Premium Payments	0	0
Plan Amendments	0	0
Actuarial Loss	(10,547)	(907)
Projected Benefit Obligation, ending balance	35,624	46,840	47,894
Funded Status	(35,624)	(46,840)
Amounts Recognized in Consolidated Balance Sheet at December 31:
Noncurrent Assets	0	0
Current Liabilities	(2,414)	(2,352)
Noncurrent Liabilities and Deferred Credits	(33,210)	(44,488)
Net Asset (Liability)	(35,624)	(46,840)
Postretirement Benefits
Change in Fair Value of Plan Assets:
Fair Value of Plan Assets, beginning balance	0	0
Actual Return on Plan Assets	0	0
Company Contributions	2,294	2,695
Benefit Payments	(8,173)	(8,385)
Participant Premium Payments	5,879	5,690
Fair Value of Plan Assets, ending balance	0	0	0
Change in Benefit Obligation:
Projected Benefit Obligation, beginning balance	69,311	70,185
Service Cost	1,338	1,722	1,847
Interest Cost	2,041	1,891	2,393
Benefit Payments	(8,172)	(8,385)
Participant Premium Payments	5,879	5,690
Plan Amendments	0	0
Actuarial Loss	(20,450)	(1,792)
Projected Benefit Obligation, ending balance	49,947	69,311	$ 70,185
Funded Status	(49,947)	(69,311)
Amounts Recognized in Consolidated Balance Sheet at December 31:
Noncurrent Assets	0	0
Current Liabilities	(2,970)	(2,830)
Noncurrent Liabilities and Deferred Credits	(46,977)	(66,481)
Net Asset (Liability)	$ (49,947)	$ (69,311)

Amount of increase (decrease) in plan assets of defined benefit plan from actual return (loss) determined by change in fair value of plan assets adjusted for contributions, benefit payments, and other expenses.

Name:	us-gaap_DefinedBenefitPlanActualReturnOnPlanAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of gain (loss) from change in actuarial assumptions which (increases) decreases benefit obligation of defined benefit plan. Assumptions include, but are not limited to, interest, mortality, employee turnover, salary, and temporary deviation from substantive plan.