Retirement Plans (Tables)

6 Months Ended

Jun. 30, 2021

Compensation And Retirement Disclosure [Abstract]

Components of Net Periodic Benefits Cost

The following tables show the components of net periodic benefits cost included in expense for the plans for the periods indicated.

							Other Post-
(in thousands)	Pension Benefits						Retirement Benefits
For The Three Months Ended June 30,	2021			2020			2021			2020
Service cost	$	2,926		$	3,208		$	21		$	28
Interest cost		2,970			4,641			67			107
Expected return on plan assets		(11,333	)		(12,797	)		—			—
Amortization of net loss and prior service costs		1,654			1,853			(163	)		(141	)
Special termination benefits		16,052			—			4,137			—
Net periodic benefit cost	$	12,269		$	(3,095	)	$	4,062		$	(6	)

							Other Post-
(in thousands)	Pension Benefits						Retirement Benefits
For the Six Months Ended June 30,	2021			2020			2021			2020
Service cost	$	6,376		$	6,483		$	48		$	50
Interest cost		6,430			8,423			166			271
Expected return on plan assets		(23,391	)		(24,097	)		—			—
Amortization of net loss and prior service costs		3,754			3,314			(309	)		(370	)
Special termination benefits		16,052			—			4,137			—
Net periodic benefit cost	$	9,221		$	(5,877	)	$	4,042		$	(49	)