Pension Plans and Other Postretirement Benefit Plans (Tables)

6 Months Ended

Jun. 30, 2021

General Discussion Of Pension And Other Postretirement Benefits [Abstract]

Components of Net Periodic Benefit Cost

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
	2021			2020			2021			2020
Three months ended June 30:
Service cost	$	6,254		$	5,550		$	897		$	980
Interest cost		6,530			6,967			1,309			1,524
Expected return on plan assets		(9,704	)		(8,625	)		(783	)		(590	)
Amortization of prior service cost		75			75			(275	)		(275	)
Net loss recognition		1,688			1,679			1,246			1,243
Net periodic benefit cost	$	4,843		$	5,646		$	2,394		$	2,882
Six months ended June 30:
Service cost	$	12,500		$	11,096		$	1,905		$	1,959
Interest cost		13,110			13,938			2,685			3,039
Expected return on plan assets		(19,479	)		(17,750	)		(1,458	)		(1,220	)
Amortization of prior service cost		150			150			(550	)		(550	)
Net loss recognition		3,511			3,333			2,419			2,486
Net periodic benefit cost	$	9,792		$	10,767		$	5,001		$	5,714