Retirement Plans (Tables)

9 Months Ended

Sep. 30, 2020

Retirement Benefits [Abstract]

Net period benefit cost for the pension and postretirement plans

The components of net periodic pension cost and net periodic benefit cost for the RAP and Postretirement Plan for the three and nine months ended September 30, 2020 and 2019 were as follows:

	Three Months Ended September 30,				Nine Months Ended September 30,
($ in Thousands)	2020		2019		2020		2019
Components of Net Periodic Benefit Cost
RAP
Service cost	$	1,853	$	1,598	$	6,183	$	5,448
Interest cost	2,124		2,489		6,139		7,314
Expected return on plan assets	(6,386)		(6,099)		(19,196)		(18,249)
Amortization of prior service cost	(18)		(18)		(55)		(55)
Amortization of actuarial loss (gain)	1,313		230		2,923		360
Total net periodic pension cost	$	(1,114)	$	(1,800)	$	(4,006)	$	(5,183)
Postretirement Plan
Interest cost	$	20	$	26	$	59	$	78
Amortization of prior service cost	(19)		(19)		(56)		(56)
Amortization of actuarial loss (gain)	—		(1)		—		(3)
Total net periodic benefit cost	$	1	$	6	$	2	$	19