Retirement Benefit Plans - Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Employees' Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Service Cost	$ 400	$ 466
Interest Cost (Benefit)	584
Interest Cost		525
Expected Return on Plan Assets	(1,009)	(932)
Amortization of Prior Service Cost	47	33
Amortization of Net Loss (Gain)	0	0
Net Periodic Benefit Cost	22	92
Plan Contributions During the Period	0	0
Estimated Future Contributions in the Current Fiscal Year	0
Select Executive Retirement Plan
Defined Benefit Plan Disclosure [Line Items]
Service Cost	26	17
Interest Cost (Benefit)	72
Interest Cost		158
Expected Return on Plan Assets	0	0
Amortization of Prior Service Cost	10	10
Amortization of Net Loss (Gain)	0	21
Net Periodic Benefit Cost	108	206
Plan Contributions During the Period	120	127
Estimated Future Contributions in the Current Fiscal Year	360
Postretirement Benefit Plans
Defined Benefit Plan Disclosure [Line Items]
Service Cost	11	15
Interest Cost (Benefit)	79
Interest Cost		81
Expected Return on Plan Assets	0	0
Amortization of Prior Service Cost	26	26
Amortization of Net Loss (Gain)	(96)	(87)
Net Periodic Benefit Cost	20	35
Plan Contributions During the Period	57	$ 27
Estimated Future Contributions in the Current Fiscal Year	$ 172