Pension Plans and Other Postretirement Benefit Plans (Tables)

6 Months Ended

Jun. 30, 2024

Retirement Benefits, Description [Abstract]

Components of Net Periodic Benefit Cost

The Company uses a December 31 measurement date for its defined benefit pension and other postretirement benefit plans. The following table sets forth the components of net periodic benefit costs for the three and six months ended June 30 (dollars in thousands):

	Pension Benefits						Other Postretirement Benefits
	2024			2023			2024			2023
Three months ended June 30:
Service cost	$	3,947		$	3,100		$	661		$	532
Interest cost		8,217			8,521			1,726			1,909
Expected return on plan assets		(11,356	)		(10,922	)		(974	)		(891	)
Curtailment loss		169			—			—			—
Amortization of prior service cost (credit)		126			123			(263	)		(263	)
Net loss recognition		569			1,185			88			(8	)
Net periodic benefit cost	$	1,672		$	2,007		$	1,238		$	1,279
Six months ended June 30:
Service cost	$	7,709		$	7,994		$	1,281		$	1,350
Interest cost		16,582			15,753			3,472			2,953
Expected return on plan assets		(22,584	)		(21,844	)		(1,948	)		(1,782	)
Curtailment loss		169			—			—			—
Amortization of prior service cost (credit)		249			246			(526	)		(526	)
Net loss recognition		1,359			2,024			179			525
Net periodic benefit cost	$	3,484		$	4,173		$	2,458		$	2,520