REVENUE RECOGNITION - Major Good or Service (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenues
Lease revenue									$ 41,956,000	$ 40,076,000	$ 31,407,000
Lease Incentive Amortization									(277,000)	(302,000)	(50,000)
Commercial Loan Investments									1,829,000	616,000	2,053,000
Revenue from contract with customer, including assessed tax									$ 852,000	2,966,000	5,191,000
Type of revenue									cto:ImpactFeeAndMitigationCreditSalesMember
Interest and Other Revenue									$ 101,000
Total Revenues	$ 11,963,117	$ 11,329,979	$ 10,688,831	$ 10,959,319	$ 12,040,174	$ 10,443,476	$ 10,805,062	$ 10,369,176	44,941,246	43,657,888	38,650,570
Lease Revenue - Base Rent
Revenues
Lease revenue									35,109,000	31,587,000	24,650,000
Lease Revenue - CAM
Revenues
Lease revenue									1,422,000	2,905,000	2,208,000
Lease Revenue - Reimbursements
Revenues
Lease revenue									2,759,000	2,934,000	2,125,000
Lease Revenue - Billboards
Revenues
Lease revenue									243,000	250,000	251,000
Above / Below Market Lease Accretion
Revenues
Lease revenue									2,382,000	2,339,000	2,194,000
Contributed Leased Assets Accretion
Revenues
Lease revenue									217,000	218,000
Management Fee Income
Revenues
Revenue from contract with customer, including assessed tax									304,000
Impact Fee and Mitigation Credit Sales
Revenues
Revenue from contract with customer, including assessed tax										1,338,000	2,126,000
Subsurface Lease Revenue
Revenues
Revenue from contract with customer, including assessed tax									598,000	957,000	856,000
Subsurface Revenue - Other
Revenues
Revenue from contract with customer, including assessed tax									150,000	668,000	2,192,000
Fill Dirt and Other Revenue
Revenues
Revenue from contract with customer, including assessed tax									104,000	3,000	17,000
Interest and Other Revenue
Revenues
Interest and Other Revenue										145,000	29,000
Income Properties
Revenues
Lease Incentive Amortization									(277,000)	(302,000)	(50,000)
Interest and Other Revenue									101,000
Total Revenues	10,594,870	10,260,831	10,375,295	10,724,418	11,728,550	9,360,155	9,781,299	9,205,727	41,955,414	40,075,731	31,406,930
Income Properties | Lease Revenue - Base Rent
Revenues
Lease revenue									35,109,000	31,587,000	24,650,000
Income Properties | Lease Revenue - CAM
Revenues
Lease revenue									1,422,000	2,905,000	2,208,000
Income Properties | Lease Revenue - Reimbursements
Revenues
Lease revenue									2,759,000	2,934,000	2,125,000
Income Properties | Lease Revenue - Billboards
Revenues
Lease revenue									243,000	250,000	251,000
Income Properties | Above / Below Market Lease Accretion
Revenues
Lease revenue									2,382,000	2,339,000	2,194,000
Income Properties | Contributed Leased Assets Accretion
Revenues
Lease revenue									217,000	218,000
Income Properties | Interest and Other Revenue
Revenues
Interest and Other Revenue										145,000	29,000
Management Services
Revenues
Total Revenues	304,553								304,553
Management Services | Management Fee Income
Revenues
Revenue from contract with customer, including assessed tax									304,000
Commercial Loan Investments
Revenues
Commercial Loan Investments									1,829,000	616,000	2,053,000
Total Revenues	920,691	855,559	52,765			41,262	273,467	300,999	1,829,015	615,728	2,052,689
Real Estate Operations
Revenues
Total Revenues	$ 143,003	$ 213,589	$ 260,771	$ 234,901	$ 311,624	$ 1,042,059	$ 750,296	$ 862,450	852,264	2,966,429	5,190,951
Real Estate Operations | Impact Fee and Mitigation Credit Sales
Revenues
Revenue from contract with customer, including assessed tax										1,338,000	2,126,000
Real Estate Operations | Subsurface Lease Revenue
Revenues
Revenue from contract with customer, including assessed tax									598,000	957,000	856,000
Real Estate Operations | Subsurface Revenue - Other
Revenues
Revenue from contract with customer, including assessed tax									150,000	668,000	2,192,000
Real Estate Operations | Fill Dirt and Other Revenue
Revenues
Revenue from contract with customer, including assessed tax									$ 104,000	$ 3,000	$ 17,000