Accumulated Other Comprehensive Loss (Reclassifications out of AOCI) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net of tax	$ (2,400)	$ (1,486)
Amortization of actuarial losses
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification	(2,657)	(1,555)
Prior service costs
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification	(141)	(138)
Pension and other post-retirement effects
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Tax benefit	398	207
Net of tax	$ (2,400)	$ (1,486)