DEBT - Debt Covenants - Excluding Timber Funds (Details) $ in Thousands	Dec. 31, 2021 USD ($)	Jun. 30, 2021 USD ($)	Dec. 31, 2020 USD ($)	Apr. 30, 2020 USD ($)	Mar. 31, 2020 USD ($)	Apr. 30, 2016 USD ($)
Incremental Term Loan Agreement borrowings due 2026 at a variable interest rate of 1.75% at December 31, 2021
Debt Instrument [Line Items]
Debt, carrying amount						$ 300,000
Excluding Timber Funds
Debt Instrument [Line Items]
Debt, carrying amount	$ 1,376,107		$ 1,294,903
Covenant EBITDA to consolidated interest expense, Covenant Requirement	2.5
Covenant EBITDA to consolidated interest expense, Actual ratio	12.6
Covenant EBITDA to consolidated interest expense, Favorable	10.1
Covenant debt to net worth plus covenant debt, Covenant Requirement	0.65
Covenant debt to net worth plus covenant debt, Actual ratio	0.43
Covenant debt to net worth plus covenant debt, favorable	0.22
Excluding Timber Funds | Revolving Credit Facility borrowings due 2025 at an average variable interest rate of 1.3% at December 31, 2021
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 300,000	$ 300,000		$ 250,000	$ 200,000
Excluding Timber Funds | Term Credit Agreement borrowings due 2028 at a variable interest rate of 1.7% at December 31, 2021
Debt Instrument [Line Items]
Debt, carrying amount	350,000		350,000
Excluding Timber Funds | Incremental Term Loan Agreement borrowings due 2026 at a variable interest rate of 1.75% at December 31, 2021
Debt Instrument [Line Items]
Debt, carrying amount	200,000	$ 300,000	$ 300,000
Excluding Timber Funds | 2021 Incremental Term Loan Facility
Debt Instrument [Line Items]
Debt, carrying amount	$ 200,000