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Transactions With Related Parties - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Related Party Transaction [Line Items]
Carrying amount of LTP's assets	$ 5.1		$ 5.1		$ 2.7
Carrying amount of LTP's liabilities	5.1		$ 5.1		$ 2.7
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	21.4	$ 22.4	$ 62.7	$ 65.5
Fiber costs from related parties	21.4	22.4	62.7	65.5
Boise Cascade Co-Owner of LTP \| Wood Products, Including Chips and Logs
Related Party Transaction [Line Items]
Fiber costs from related parties	$ 4.4	$ 4.1	$ 13.2	$ 12.8
Packaging Corporation of America
Related Party Transaction [Line Items]
Variable interest entity, ownership percentage			50.00%