Employee Benefit Plans (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Defined benefit pension plan
Defined Benefit Plan Disclosure [Line Items]
Interest cost	$ 1,099	$ 1,255	$ 3,234	$ 4,342
Expected return on plan assets	(1,812)	(2,022)	(5,460)	(6,333)
Pension settlement	(376)	(437)	(1,364)	(567)
Amortization of prior service costs (credits)	(52)	(27)	(139)	(83)
Net benefit cost (credit)	(1,141)	(1,231)	(3,729)	(2,641)
Other postretirement benefits plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	86	104	256	316
Interest cost	529	543	1,585	1,849
Amortization of other actuarial losses (gains)		(160)		(1,219)
Net benefit cost (credit)	$ 615	$ 487	$ 1,841	$ 946