Retirement Benefits Change in Net Benefit Obligation (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2023	Dec. 31, 2022
Qualified Pension Benefits [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Defined Benefit Plan, Benefit Obligation, Beginning Balance	$ 589,278	$ 834,960
Defined Benefit Plan, Service Cost	4,632	26,351
Defined Benefit Plan, Interest Cost	7,929	24,263
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)	0	(215,005)
Defined Benefit Plan, Benefit Obligation, Benefits Paid	(11,625)	(80,226)
Administrative Expense	0	(1,065)
Defined Benefit Plan, Benefit Obligation, Ending Balance	590,214	589,278
Supplemental Employee Retirement Plan [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Defined Benefit Plan, Benefit Obligation, Beginning Balance	32,046	43,155
Defined Benefit Plan, Service Cost	71	557
Defined Benefit Plan, Interest Cost	424	1,253
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)	0	(5,260)
Defined Benefit Plan, Benefit Obligation, Benefits Paid	(485)	(7,659)
Administrative Expense	0	0
Defined Benefit Plan, Benefit Obligation, Ending Balance	32,056	32,046
Other Benefit [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Defined Benefit Plan, Benefit Obligation, Beginning Balance	9,015	11,654
Defined Benefit Plan, Benefit Obligation, Increase (Decrease) for Plan Amendment	0	38
Defined Benefit Plan, Service Cost	47	217
Defined Benefit Plan, Interest Cost	115	311
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)	0	(2,397)
Defined Benefit Plan, Benefit Obligation, Benefits Paid	(438)	(808)
Administrative Expense	0	0
Defined Benefit Plan, Benefit Obligation, Ending Balance	8,739	9,015
Qualified Plan [Member] | Qualified Pension Benefits [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Defined Benefit Plan, Benefit Obligation, Increase (Decrease) for Plan Amendment	0	0
Nonqualified Plan [Member] | Supplemental Employee Retirement Plan [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Defined Benefit Plan, Benefit Obligation, Increase (Decrease) for Plan Amendment	$ 0	$ 0