IMPAIRMENT OF LONG-LIVED ASSETS (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment of long-lived assets	$ (9.0)	$ (92.0)
Impairment of long-lived assets			$ 11.0
Nonoperating Assets in Canada, Minnesota and Texas [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment of long-lived assets		47.0
EWP Facility Producing LSL and OSB [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment of long-lived assets		39.0
Siding Facility Expected To Sell [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment of long-lived assets		$ 5.0