Pension Plans and Other Postretirement Benefit Plans (Tables)

9 Months Ended

Sep. 30, 2021

Retirement Benefits, Description [Abstract]

Components of Net Periodic Benefit Cost

The following table sets forth the components of net periodic benefit costs for the three and nine months ended September 30 (dollars in thousands):

	Pension Benefits						Other Postretirement Benefits
	2021			2020			2021			2020
Three months ended September 30:
Service cost	$	6,412		$	5,549		$	1,062		$	982
Interest cost		6,528			6,968			1,305			1,524
Expected return on plan assets		(9,835	)		(8,625	)		(509	)		(590	)
Amortization of prior service cost		75			75			(275	)		(275	)
Net loss recognition		1,592			1,678			777			1,243
Net periodic benefit cost	$	4,772		$	5,645		$	2,360		$	2,884
Nine months ended September 30:
Service cost	$	18,912		$	16,645		$	2,967		$	2,941
Interest cost		19,638			20,906			3,990			4,563
Expected return on plan assets		(29,314	)		(26,375	)		(1,967	)		(1,810	)
Amortization of prior service cost		225			225			(825	)		(825	)
Net loss recognition		5,103			5,011			3,196			3,729
Net periodic benefit cost	$	14,564		$	16,412		$	7,361		$	8,598