Employee Benefit Plans (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Defined benefit pension plan
Defined Benefit Plan Disclosure [Line Items]
Interest cost	$ 1,483	$ 2,259	$ 3,087	$ 4,517
Expected return on plan assets	(2,023)	(2,724)	(4,311)	(5,447)
Pension settlement	(134)	(429)	(130)	(429)
Amortization of prior service costs (credits)	(27)		(54)	0
Net benefit credit	(701)	(894)	(1,408)	(1,359)
Other postretirement benefits plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	106	120	212	240
Interest cost	653	877	1,306	1,753
Amortization of other actuarial losses (gains)	(529)		(1,059)	0
Net benefit credit	$ 230	$ 997	$ 459	$ 1,993