Summary of Significant Accounting Policies (Narrative) (Details) a in Millions	12 Months Ended
	Dec. 31, 2021 USD ($) a	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Principle Accounting Policies [Line Items]
Timber And Timberlands Acres Owned | a	1.8
Loss on disposal of property	$ 1,700,000	$ 0	$ 900,000
Gross carrying amount of long-lived intangible assets	8,400,000	8,400,000
Accumulated amortization	3,100,000	2,300,000
Indefinite-lived intangible assets, trade names	10,200,000	10,200,000
Impairment of intangible assets	$ 0	0	0
Defined benefit obligation of plan assets description	amortization of cumulative unrecognized net actuarial gains and losses – generally in excess of 10 percent of the greater of the benefit obligation or market-related value of plan assets at the beginning of the year – over the average remaining service period of the active employee group covered by the plan.
Long-term principal	$ 762,235,000	762,235,000
Variable Rate Term Loans [Member]
Principle Accounting Policies [Line Items]
Long-term principal	403,500,000	403,500,000
Designated as Hedging Instrument [Member]
Principle Accounting Policies [Line Items]
Derivative Fair Value Of Derivative Net	0	0
Customer Relationship and Trade Names [Member]
Principle Accounting Policies [Line Items]
Amortization expense	800,000	$ 800,000	$ 800,000
Intangible assets estimated amortization expense, year one	800,000
Intangible assets estimated amortization expense, year two	800,000
Intangible assets estimated amortization expense, year three	800,000
Intangible assets estimated amortization expense, year four	800,000
Intangible assets estimated amortization expense, year five	$ 800,000
Intangible Assets, Amortization Period [Member] | Customer Relationships [Member]
Principle Accounting Policies [Line Items]
Finite-lived intangible asset, useful life	10 years
Intangible Assets, Amortization Period [Member] | Trade Names [Member]
Principle Accounting Policies [Line Items]
Finite-lived intangible asset, useful life	20 years
Minimum [Member]
Principle Accounting Policies [Line Items]
Operating leases, options to extend leases term	1 year
Maximum [Member]
Principle Accounting Policies [Line Items]
Operating leases, options to extend leases term	5 years
Timber and Timberlands [Member] | Minimum [Member]
Principle Accounting Policies [Line Items]
Timber volume estimate, review period	5 years
Property, plant and equipment, useful life	5 years
Timber and Timberlands [Member] | Maximum [Member]
Principle Accounting Policies [Line Items]
Timber volume estimate, review period	10 years
Property, plant and equipment, useful life	20 years
Ola, Arkansas Sawmill [Member]
Principle Accounting Policies [Line Items]
Write off of property and equipment	$ 9,500,000
Equipment disposal costs	$ 2,595,000