Accumulated Other Comprehensive Income (Schedule of Accumulated Other Comprehensive Income (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2021 USD ($)
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	$ 283,561
Unrealized gains (losses)	176
Amounts reclassified from AOCI	1,161
Ending Balance	281,443
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(35,701)
Ending Balance	(34,364)
Derivative instruments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(3,891)
Unrealized gains (losses)	65
Amounts reclassified from AOCI	624
Ending Balance	(3,202)
Pension, postretirement and other post-employment benefits
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(31,459)
Amounts reclassified from AOCI	547
Ending Balance	(30,912)
Available-for-sale securities
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(351)
Unrealized gains (losses)	111
Amounts reclassified from AOCI	(10)
Ending Balance	$ (250)