Property, Plant and Equipment (Narrative) (Details) - USD ($) $ in Millions	1 Months Ended	12 Months Ended			28 Months Ended
	Sep. 30, 2023	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Sep. 30, 2023
Property Plant And Equipment [Line Items]
Depreciation expense		$ 43.5	$ 44.6	$ 37.6
Ola, Arkansas Sawmill [Member]
Property Plant And Equipment [Line Items]
Deductible amount of property damage and business interruption losses	$ 2.0	2.0
Proceeds from insurance of claim received		0.0	39.4	34.1	$ 89.4
Business interruption recoveries		1.7	36.4	26.2
Property damage recoveries		0.0	1.4	8.8
Net of disposal costs and fixed asset write-offs		0.0	0.0	0.9
Waldo Arkansas Sawmill [Member]
Property Plant And Equipment [Line Items]
Capitalized cost of expansion and modernization		131.0
Project expansion and modernization cost		44.6	74.2	12.2
Additional depreciation expense		$ 8.2	$ 11.9	$ 7.0