ENVIRONMENTAL REMEDIATION LIABILITIES (Details) $ in Millions	5 Months Ended	9 Months Ended
	Sep. 30, 2020 USD ($)	Sep. 30, 2020 USD ($)
Property, Plant and Equipment [Line Items]
Payments for ongoing environmental remediation efforts	$ 0.2
Accrual for environmental remediation	$ 11.7	$ 11.7
Minimum | Millsite Cleanup And Natural Resource Damages Restoration
Property, Plant and Equipment [Line Items]
Natural resource damages restoration monitoring term		2 years
Minimum | Port Gamble Location
Property, Plant and Equipment [Line Items]
Natural resource damages restoration monitoring term		10 years
Maximum | Millsite Cleanup And Natural Resource Damages Restoration
Property, Plant and Equipment [Line Items]
Natural resource damages restoration monitoring term		3 years
Maximum | Port Gamble Location
Property, Plant and Equipment [Line Items]
Natural resource damages restoration monitoring term		15 years