Special Purpose Entities - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2023	Sep. 30, 2023
Timber Notes [Member] | Level 2 [Member]
Debt Instrument [Line Items]
Fair value of restricted assets held by SPEs		$ 1,257.2
Non-recourse Liabilities [Member] | Level 2 [Member]
Debt Instrument [Line Items]
Fair value of non-recourse liabilities held by SPEs		$ 1,112.4
MeadWestvaco [Member] | Timber Note II [Member] | Installment Note Receivable, Maturity in December 2023 [Member]
Debt Instrument [Line Items]
Restricted assets held by special purpose entities	$ 860.0
Receipt from related SPE entity to Company, net of interest and other items	88.1
MeadWestvaco [Member] | Timber Note II [Member] | Secured Financing Liability, Maturity in December 2023 [Member]
Debt Instrument [Line Items]
Non-recourse liabilities held by special purpose entities	$ 774.0