TAXABLE INCOME AND TAX BASIS (Details)	12 Months Ended
	Dec. 31, 2020 USD ($)
TAXABLE INCOME AND TAX BASIS
Taxable net income	$ 8,578,000
Excess amount of statement income over taxable income	7,153,000
Excess amount of cumulative statement basis over cumulative taxable basis	7,332,000
Excess amount of statement income from joint venture investments over taxable income	$ 1,476,000