Employee Benefit Plans (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Defined benefit pension plan
Defined Benefit Plan Disclosure [Line Items]
Interest cost	$ 1,068	$ 1,604
Expected return on plan assets	(1,824)	(2,288)
Pension settlement		4
Amortization of prior service costs (credits)	(28)	(28)
Net benefit cost (credit)	(784)	(708)
Other postretirement benefits plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	85	106
Interest cost	528	653
Amortization of other actuarial losses (gains)		(530)
Net benefit cost (credit)	$ 613	$ 229