Employee Benefit Plans (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Defined benefit pension plan
Defined Benefit Plan Disclosure [Line Items]
Interest cost	$ 1,255	$ 1,922	$ 4,342	$ 6,439
Expected return on plan assets	(2,022)	(2,699)	(6,333)	(8,146)
Pension settlement	(437)	(197)	(567)	(626)
Amortization of prior service costs (credits)	(27)	4	(83)	4
Net benefit credit	(1,231)	(970)	(2,641)	(2,329)
Other postretirement benefits plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	104	120	316	360
Interest cost	543	876	1,849	2,629
Amortization of other actuarial losses (gains)	(160)	(2,236)	(1,219)	(2,236)
Net benefit credit	$ 487	$ (1,240)	$ 946	$ 753