Retirement Plans (Tables)

6 Months Ended

Jun. 30, 2019

Compensation And Retirement Disclosure [Abstract]

Components of Net Periodic Benefits Cost

							Other Post-
(in thousands)	Pension Benefits						Retirement Benefits
For the Three Months Ended June 30,	2019			2018			2019			2018
Service cost	$	2,735		$	3,163		$	22		$	28
Interest cost		4,661			4,279			164			161
Expected return on plan assets		(11,300	)		(10,169	)		—			—
Amortization of net loss and prior service costs		2,552			1,365			(228	)		(94	)
Net periodic benefit cost (reduction of cost)	$	(1,352	)	$	(1,362	)	$	(42	)	$	95

							Other Post-
(in thousands)	Pension Benefits						Retirement Benefits
For the Six Months Ended June 30,	2019			2018			2019			2018
Service cost	$	5,510		$	6,088		$	51		$	63
Interest cost		9,524			8,202			292			298
Expected return on plan assets		(22,600	)		(19,869	)		—			—
Amortization of net loss and prior service costs		4,982			2,691			(455	)		(243	)
Net periodic benefit cost (reduction of cost)	$	(2,584	)	$	(2,888	)	$	(112	)	$	118