Pension and Other Postretirement Benefits (Tables)

6 Months Ended

Jun. 30, 2018

Retirement Benefits [Abstract]

Schedule of components of net periodic benefit cost

Components of net periodic benefit cost were as follows:

	Pension Benefits						Postretirement Benefits
	Three months ended June 30,
(in thousands)	2018			2017			2018			2017
Components of net periodic benefit cost
Service cost	$	2,259		$	2,184		$	154		$	243
Interest cost	2,989			2,934			118			183
Expected return on plan assets	(3,198		)	(2,934		)	—			—
Settlement expense	464			185			—			—
Amortization of net (gain) loss	732			258			(419		)	(135		)
Amortization of prior service cost (credit)	43			43			(34		)	(27		)
Net periodic benefit cost (income)	$	3,289		$	2,670		$	(181	)	$	264

	Pension Benefits						Postretirement Benefits
	Six months ended June 30,
(in thousands)	2018			2017			2018			2017
Components of net periodic benefit cost
Service cost	$	4,702		$	4,521		$	329		$	478
Interest cost	5,947			5,952			245			357
Expected return on plan assets	(6,477		)	(5,947		)	—			—
Settlement expense	472			316			—			—
Amortization of net (gain) loss	1,252			297			(770		)	(301		)
Amortization of prior service cost (credit)	87			87			(68		)	(68		)
Net periodic benefit cost (income)	$	5,983		$	5,226		$	(264	)	$	466