Retirement Plans and Other Postretirement Benefits (Tables)

12 Months Ended

Dec. 31, 2021

Retirement Benefits [Abstract]

Summary of Retirement Plans and Other Postretirement Benefits

Information with respect to the Retirement Plans and Other Postretirement Benefits follows:

	Retirement Plans				Other Postretirement Benefits
(Dollars in thousands)	2021		2020		2021		2020
Change in benefit obligation:
Benefit obligation at beginning of year	$	59,431	$	53,685	$	3,540	$	3,069
Service cost	567		477		143		109
Interest cost	1,431		1,692		85		96
Actuarial (gain) loss	(1,043)		6,423		(124)		377
Benefits paid	(2,688)		(2,846)		(108)		(111)
Benefit obligation at end of year	$	57,698	$	59,431	$	3,536	$	3,540
Change in plan assets:
Fair value of plan assets at beginning of year	$	55,366	$	51,607	$	—	$	—
Actual return on plan assets	7,644		6,306		—		—
Benefits paid	(2,688)		(2,846)		(108)		(111)
Corrective payment	—		140		—		—
Employer contribution and non-qualified benefit payments	157		159		108		111
Fair value of plan assets at end of year	$	60,479	$	55,366	$	—	$	—
Funded status	2,781		(4,065)		(3,536)		(3,540)
Unrecognized net actuarial loss	18,226		24,526		820		989
Net amount recognized	$	21,007	$	20,461	$	(2,716)	$	(2,551)

The net actuarial (gain) loss for December 31, 2021 and 2020 was the result of changes in the discount rate, interest crediting rate, life insurance data and driven by mortality losses on retirees, as well as greater than anticipated salary increases.

Components of Net Periodic Benefit Cost (Income)

Components of net periodic benefit (income) cost were as follows: 

	Retirement Plans						Other Postretirement Benefits
(Dollars in thousands)	2021		2020		2019		2021		2020		2019
Service cost	$	567	$	477	$	436	$	143	$	109	$	67
Interest cost	1,431		1,692		1,905		85		96		94
Expected loss on plan assets	(3,656)		(3,291)		(3,061)		—		—		—
Amortization of net actuarial loss	1,269		1,176		1,176		47		26		—
Accretion of prior service cost	—		—		(181)		—		—		—
Net periodic benefit (income) cost	$	(389)	$	54	$	275	$	275	$	231	$	161

Expected Amortization Expense

(Dollars in thousands)	Retirement Plans		Other Postretirement Benefits
Expected amortization expense for 2022:
Amortization of net actuarial loss	$	818	$	55

Summary of Benefit Payments Expected to be Paid

The following benefits payments, which reflect expected future service, as appropriate, are expected to be paid:

(Dollars in thousands)	Retirement Plans		Other Postretirement Benefits
For the fiscal year ending:
2022	$	2,995	$	127
2023	3,077		130
2024	3,114		135
2025	3,107		137
2026	3,143		142
Years 2027-2031	15,576		957
Total	$	31,012	$	1,628

Weighted-Average Assumptions Used to Determine Benefit Obligations

Weighted-average assumptions used to determine benefit obligations at December 31, 2021 and 2020 were as follows:

	Retirement Plans				Other Postretirement Benefits
	2021		2020		2021		2020
Assumed discount rate	2.8	%	2.4	%	2.8	%	2.4	%
Assumed salary increase rate	3%-6%		3%-6%		—		—

The benefit obligation for all plans at December 31, 2021 was based on the Pri-2012 White Collar Dataset Mortality Table with scale MP-2021 fully generational published by the Society of Actuaries. The discount rate is based on matching the Plan's projected cash flows to the spot rates in FTSE Pension Above Median Double-A Curve as of the disclosure date. The assumed salary increase considers available service years from the valuation date through the participant's normal retirement date.

Weighted-average assumptions used to determine net periodic costs for the years ended December 31, 2021 and 2020 were as follows:

	Retirement Plans				Other Postretirement Benefits
	2021		2020		2021		2020
Assumed discount rate	2.4	%	3.2	%	2.4	%	3.2	%
Assumed long-term rate of investment return	6.5	%	6.5	%	—		—
Assumed salary increase rate	3%-6%		3%-6%		—		—
Assumed cash balance interest crediting rate	2.0	%	2.0	%	—		—

Summary of Corporation's Pension Plan Asset Allocation

The Corporation's pension plan asset allocation at December 31, 2021 and 2020, by asset category was as follows:

	Percentage of Plan Assets at December 31,
	2021		2020
Asset Category:
Equity securities	64	%	60	%
Debt securities	34		37
Other	2		3
Total	100	%	100	%

Major Categories of Assets in Corporation's Pension Plan

The major categories of assets in the Corporation's pension plan at year-end are presented in the following table. Assets are segregated by the level of the valuation inputs within the fair value hierarchy described in Note 19, "Fair Value Disclosures."

	Fair Value Measurements at December 31,
(Dollars in thousands)	2021		2020
Level 1:
Mutual funds	$	41,951	$	37,602
Short-term investments	1,619		1,984
Level 2:
U.S. government obligations	7,050		5,721
Corporate bonds	6,536		6,204
Certificates of deposit	3,323		3,855
Total fair value of plan assets	$	60,479	$	55,366