Income Taxes (Schedule of Components of Deferred Income Tax Assets and Liabilities) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Pensions	$ 16,807	$ 38,986
Postretirement employee benefits	18,464	20,293
Nondeductible accruals	2,405	3,841
Inventories	2,636	3,126
Incentive compensation	2,807	2,843
Tax credits	2,135	2,678
Employee benefits	1,586	1,795
Net operating loss carryforwards	1,056	1,346
Other	200	124
Deferred Tax Assets, Total	48,096	75,032
Valuation allowance	(2,184)	(2,867)
Deferred tax assets, net of valuation allowance	45,912	72,165
Timber and timberlands	(5,871)	(6,006)
Property, plant and equipment	(10,741)	(12,360)
Deferred tax liabilities, total	(16,612)	(18,366)
Net deferred tax assets	$ 29,300	$ 53,799