Income Taxes (Schedule of Components of Deferred Income Tax Assets and Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Pension and other postretirement employee benefits	$ 22,610	$ 34,703
Inventories	387	552
Tax credits		1,519
Nondeductible accruals	1,634	2,005
Incentive compensation	1,437	971
Employee benefits	1,444	1,323
Other	598	1,110
Total deferred tax assets	28,110	42,183
Timber and timberlands, net	(226)	(354)
Property, plant and equipment, net	(53,800)	(52,698)
Intangible assets, net	(3,466)	(3,656)
Real estate development	(2,476)	(1,236)
Other	(3,016)	(1,979)
Total deferred tax liabilities	(62,984)	(59,923)
Deferred tax liabilities, net	$ (34,874)	$ (17,740)