Segment Information (Summary of Information by Business Segment) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Adjusted EBITDDA		$ 652,871	$ 382,228	$ 178,943
Interest expense, net	[1]	(29,275)	(29,463)	(30,361)
Depreciation, depletion and amortization		(75,633)	(76,261)	(70,417)
Basis of real estate sold		(27,360)	(25,348)	(20,554)
Net gain on fire damage		3,361
Loss on the extinguishment of debt				(5,512)
Pension settlement charge			(42,988)
Non-operating pension and other postretirement employee benefits		(13,227)	(14,226)	(3,739)
(Loss) gain on fixed assets		(1,721)	11	(865)
Gain on sale of facility				9,176
Income before income taxes		509,016	193,953	56,671
Operating Segments [Member]
Segment Reporting Information [Line Items]
Depreciation, depletion and amortization		75,633	76,261	70,417
Operating Segments [Member] | Timberlands [Member]
Segment Reporting Information [Line Items]
Adjusted EBITDDA		262,944	182,802	133,987
Depreciation, depletion and amortization		45,403	51,047	46,601
Operating Segments [Member] | Wood Products [Member]
Segment Reporting Information [Line Items]
Adjusted EBITDDA		393,858	176,095	12,901
Depreciation, depletion and amortization		28,802	23,611	22,059
Operating Segments [Member] | Real Estate Segment [Member]
Segment Reporting Information [Line Items]
Adjusted EBITDDA		47,457	86,476	62,650
Depreciation, depletion and amortization		640	620	678
Basis of real estate sold		(27,381)	(25,990)	(20,749)
Corporate [Member]
Segment Reporting Information [Line Items]
Adjusted EBITDDA		(47,393)	(48,451)	(36,257)
Depreciation, depletion and amortization		788	983	1,079
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Adjusted EBITDDA		(3,995)	(14,694)	5,662
Basis of real estate sold		$ 21	$ 642	$ 195

[1] Includes amortization of bond discounts and deferred loan fees.