Retirement Benefit Plans (Fair Values of Pension Plan Assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Total Assets including Common Trust Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 723,064	$ 700,535
Level 1 [Member] | Total Assets including Common Trust Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	175,171	200,500
Level 2 [Member] | Total Assets including Common Trust Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	38,750	31,268
Pension Benefits [Member] | Cash And Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	5,268	9,050
Pension Benefits [Member] | Total Cash and Cash-Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	5,268	9,050
Pension Benefits [Member] | Fixed Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	64,289	60,845
Pension Benefits [Member] | Mutual Fund-Fixed Income [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		344
Pension Benefits [Member] | Exchange Traded Fund (ETF)-Fixed Income [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	3,434	5,087
Pension Benefits [Member] | Total Fixed Income [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	67,723	66,276
Pension Benefits [Member] | Domestic And Foreign Stock [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	45,864	50,956
Pension Benefits [Member] | Mutual Funds-Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	95,066	105,486
Pension Benefits [Member] | Total Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	140,930	156,442
Pension Benefits [Member] | Total Real Assets At Fair Value [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	213,921	231,768
Pension Benefits [Member] | Common Trust Fund (Fixed Income) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	451,493	410,280
Pension Benefits [Member] | Common Trust Fund (Real Assets) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	57,650	58,487
Pension Benefits [Member] | Level 1 [Member] | Cash And Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	5,268	9,050
Pension Benefits [Member] | Level 1 [Member] | Total Cash and Cash-Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	5,268	9,050
Pension Benefits [Member] | Level 1 [Member] | Fixed Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	25,539	29,577
Pension Benefits [Member] | Level 1 [Member] | Mutual Fund-Fixed Income [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		344
Pension Benefits [Member] | Level 1 [Member] | Exchange Traded Fund (ETF)-Fixed Income [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	3,434	5,087
Pension Benefits [Member] | Level 1 [Member] | Total Fixed Income [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	28,973	35,008
Pension Benefits [Member] | Level 1 [Member] | Domestic And Foreign Stock [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	45,864	50,956
Pension Benefits [Member] | Level 1 [Member] | Mutual Funds-Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	95,066	105,486
Pension Benefits [Member] | Level 1 [Member] | Total Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	140,930	156,442
Pension Benefits [Member] | Level 1 [Member] | Total Real Assets At Fair Value [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	175,171	200,500
Pension Benefits [Member] | Level 2 [Member] | Fixed Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	38,750	31,268
Pension Benefits [Member] | Level 2 [Member] | Total Fixed Income [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	38,750	31,268
Pension Benefits [Member] | Level 2 [Member] | Total Real Assets At Fair Value [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 38,750	$ 31,268