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Transactions With Related Parties - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Related Party Transaction [Line Items]
Carrying amount of LTP's assets	$ 7,347.6		$ 7,235.8
Boise Cascade Co-Owner of LTP
Related Party Transaction [Line Items]
Variable interest entity, ownership percentage	50.00%
Boise Cascade Co-Owner of LTP \| Fiber
Related Party Transaction [Line Items]
Revenue from related parties	$ 22.6	$ 20.0
Fiber costs from related parties	22.6	20.0
Boise Cascade Co-Owner of LTP \| Wood Products, Including Chips and Logs
Related Party Transaction [Line Items]
Fiber costs from related parties	$ 4.2	$ 4.4
Packaging Corporation of America
Related Party Transaction [Line Items]
Variable interest entity, ownership percentage	50.00%
Variable Interest Entity
Related Party Transaction [Line Items]
Carrying amount of LTP's assets	$ 5.0		3.9
Carrying amount of LTP's liabilities	$ 5.0		$ 3.9