Retirement Benefits (Tables)

3 Months Ended

Mar. 31, 2026

Retirement Benefits [Abstract]

Schedule of Components of Net Periodic Benefit Cost (Credit)

The components of the net periodic pension benefit cost for the three months ended March 31 were as follows:

	2026		2025
	(Dollars in thousands)
Service cost	$	1,582	$	1,944
Interest cost	7,681		8,119
Expected return on plan assets	(10,409)		(10,257)
Amortization of prior service (credit) cost	(13)		8
Amortization of actuarial losses	1,782		1,893
Net periodic benefit cost	$	623	$	1,707

The components of the net periodic other postretirement benefit (credit) cost for the three months ended March 31 were as follows:

	2026		2025
	(Dollars in thousands)
Service cost	$	3	$	4
Interest cost	92		151
Amortization of prior service credit	(16)		(15)
Amortization of actuarial gains	(157)		(86)
Net periodic benefit (credit) cost	$	(78)	$	54