SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Narrative) (Details)	3 Months Ended								12 Months Ended
	Dec. 31, 2019 USD ($) Partner $ / shares shares	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($) a shares	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2019 USD ($) fund Partner Segment $ / shares shares	Dec. 31, 2018 USD ($) a parcel_of_land shares	Dec. 31, 2017 USD ($)	Jan. 01, 2019 USD ($)
Significant Accounting Policies [Line Items]
Number of private equity timber funds | fund									3
Number of segments | Segment									4
Revenue	$ 28,938,000	$ 27,948,000	$ 27,975,000	$ 25,042,000	$ 22,647,000	$ 28,008,000	$ 27,912,000	$ 24,987,000
Number of general partners | Partner	2								2
Number of partnership units owned by general partners (in shares) | shares	60,000				60,000				60,000	60,000
Other assets	$ 6,635,000				$ 9,255,000				$ 6,635,000	$ 9,255,000
Allowance for doubtful accounts on accounts receivable	0				0				0	0
Deferred tax assets, valuation allowance	0								0
Interest expense and penalties on taxes									0	$ 0	$ 0
Number of parcels of land held-for-sale | parcel_of_land										3
Deferred revenue	223,000				336,000				223,000	$ 336,000
Operating lease, right-of-use asset	161,000								$ 161,000
Restricted Units
Significant Accounting Policies [Line Items]
Vesting period of restricted stock unit award									4 years
Land
Significant Accounting Policies [Line Items]
Land held for sale	0				$ 5,700,000				$ 0	$ 5,700,000
Area of land for sale (in acres) | a					20					20
Like-Kind Intermediaries
Significant Accounting Policies [Line Items]
Other assets	$ 0				$ 0				$ 0	$ 0
General Partners
Significant Accounting Policies [Line Items]
Number of partnership units owned by general partners (in shares) | shares	60,000								60,000
Fund II, III, and IV | Series A Preferred Stock
Significant Accounting Policies [Line Items]
Preferred stock issued (in shares) | shares	125								125
Preferred stock issued at par value (in dollars per share) | $ / shares	$ 0.01								$ 0.01
Series A preferred stock (in dollars per share) | $ / shares	1,000								1,000
Preferred stock, liquidation preference (in dollars per share) | $ / shares	$ 1,000								$ 1,000
Fund IV | Series A Preferred Stock
Significant Accounting Policies [Line Items]
Preferred stock rate of interest									12.00%
Fund II and Fund III | Series A Preferred Stock
Significant Accounting Policies [Line Items]
Preferred stock rate of interest									12.50%
Maximum amount required to pay on redemption upon settlement	$ 125,000								$ 125,000
Accounting Standards Update 2016-02 [Member]
Significant Accounting Policies [Line Items]
Operating lease, right-of-use asset												$ 294,000
Operating lease liability												$ 294,000
Topic 606 | Difference due to Topic 606 | Timber deed sale revenue
Significant Accounting Policies [Line Items]
Revenue									$ (3,200,000)	$ 7,400,000
Ferncliff Investors ownership
Significant Accounting Policies [Line Items]
Percentage of interests owned by third parties in non controlling interests	66.67%								66.67%
Fund II, III, and IV | Olympic Resource Management Llc
Significant Accounting Policies [Line Items]
Ownership interest									1.00%
Fund II
Significant Accounting Policies [Line Items]
Percentage of interests owned by third parties in non controlling interests	80.00%								80.00%
Fund II | Partnership Timber
Significant Accounting Policies [Line Items]
Ownership interest									19.00%
Fund III
Significant Accounting Policies [Line Items]
Percentage of interests owned by third parties in non controlling interests	95.00%								95.00%
Fund III | Partnership Timber
Significant Accounting Policies [Line Items]
Ownership interest									4.00%
Fund IV
Significant Accounting Policies [Line Items]
Percentage of interests owned by third parties in non controlling interests	85.00%								85.00%
Fund IV | Partnership Timber
Significant Accounting Policies [Line Items]
Ownership interest									14.00%
Ferncliff Investors | Ferncliff Management
Significant Accounting Policies [Line Items]
Ownership interest									33.33%
Bainbridge Landing | Ferncliff Investors
Significant Accounting Policies [Line Items]
Percentage of ownership interest in Funds	50.00%								50.00%