Employee benefit plans (Tables)

12 Months Ended

Dec. 31, 2023

Employee benefit plans

Summary of pension and postretirement life insurance plans

	Pension Benefits
(Dollars in thousands)	2023		2022
Change in benefit obligation:
Benefit obligation, beginning	$	13,792	$	18,066
Interest cost		655		456
Change in experience gain		2		26
Change in actuarial assumptions		306		(3,899)
Benefits paid		(910)		(857)
Benefit obligation, ending		13,845		13,792
Change in plan assets:
Fair value of plan assets, beginning		16,106		19,257
Actual return on plan assets		2,413		(2,294)
Employer contributions
Benefits paid		(910)		(857)
Fair value of plan assets, ending		17,609		16,106
Funded status at end of year	$	3,764	$	2,314

Schedule of amounts recognized in balance sheet

	Pension Benefits
(Dollars in thousands)	2023		2022
(Other Assets)/Other Liabilities	$	(3,764)	$	(2,314)
Amounts recognized in the accumulated other comprehensive loss consist of:
Net actuarial gain		(4,370)		(5,499)
Deferred taxes		956		1,184
Net amount recognized	$	(3,414)	$	(4,315)

Schedule of components of net periodic benefit cost

(Dollars in thousands)	Pension Benefits
Twelve Months Ended December 31,	2023		2022		2021
Net periodic pension income:
Interest cost	$	655	$	456	$	419
Expected return on plan assets		(1,170)		(1,407)		(1,288)
Amortization of unrecognized net loss		194		198		301
Net periodic pension income:		(321)		(753)		(568)
Other changes in plan assets and benefit obligations recognized in other comprehensive income (loss):
Net loss		655		456		419
Deferred tax		(141)		(96)		(88)
Total recognized in other comprehensive income (loss)		514		360		331
Total recognized in net period pension cost and other comprehensive income (loss)	$	193	$	(393)	$	(237)

Schedule of weighted-average assumptions used to determine benefit obligations and related expenses

	Pension Benefits
	2023		2022		2021
Discount rate:
Obligation	4.73	%	4.93	%	2.59	%
Expense	4.93		2.59		2.25
Expected long-term return on plan assets	7.50	%	7.50	%	7.50	%

Schedule of pension plan weighted-average asset allocations

	2023		2022
Asset Category:
Cash and cash equivalents	4.4	%	4.7	%
Equity securities	63.3		60.3
Corporate bonds	18.1		19.5
U.S. government securities	14.2		15.5
	100.0	%	100.0	%

Schedule of fair value measurement of pension plan assets

	December 31, 2023
			Quoted Prices in
			Active Markets		Significant		Significant
			for Identical		Observable		Observable
			Assets		Inputs		Inputs
(Dollars in thousands)	Total		(Level 1)		(Level 2)		(Level 3)
Cash and cash equivalents	$	783	$	783	$		$
Equity securities:
U.S. large cap		9,482		9,482
International		1,671		1,671
Fixed income securities:
U.S. Treasuries		343				343
U.S. government agencies		2,149				2,149
Corporate bonds		3,181				3,181
Total	$	17,609	$	11,936	$	5,673	$

	December 31, 2022
			Quoted Prices in
			Active Markets		Significant		Significant
			for Identical		Observable		Observable
			Assets		Inputs		Inputs
(Dollars in thousands)	Total		(Level 1)		(Level 2)		(Level 3)
Cash and cash equivalents	$	759	$	759	$		$
Equity securities:
U.S. large cap		7,365		7,365
International		2,338		2,338
Fixed income securities:
U.S. Treasuries		511				511
U.S. government agencies		1,991				1,991
Corporate bonds		3,142				3,142
Total	$	16,106	$	10,462	$	5,644	$

Schedule of expected benefit payments

(Dollars in thousands)	Pension Benefits
2024	$	966
2025		999
2026		1,022
2027		1,030
2028		1,024
Thereafter		4,946