Retirement Benefits (Tables)

3 Months Ended

Mar. 31, 2021

Defined Benefit Plan Disclosure [Line Items]

Summary Of Net Periodic Benefit Cost

Pension Benefits	Three Months Ended
	March 31,
(Dollars in thousands)	2021		2020
Service cost	$	2,738	$	4,011
Interest cost		1,999		2,483
Expected return on plan assets		(5,580)		(5,197)
Amortization of net (income) loss		2,730		1,213
Net periodic benefit cost	$	1,887	$	2,510

Other Benefits	Three Months Ended
	March 31,
(Dollars in thousands)	2021		2020
Service cost	$	281	$	141
Interest cost		181		215
Amortization of prior service cost		(144)		(48)
Net periodic benefit cost	$	318	$	308
(Some amounts may not reconcile due to rounding.)