Amount, before tax, of (gain) loss recognized for the (reversal of write-down) write-down to fair value, less cost to sell, of a disposal group. Excludes discontinued operations.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=84176398&loc=d3e2941-110230

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=68055307&loc=d3e2443-110228

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585

Name:	us-gaap_DisposalGroupNotDiscontinuedOperationLossGainOnWriteDown
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

INCOME PROPERTIES - Dispositions of Income Properties and Impairment Charges (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2016 USD ($) property	Mar. 31, 2016 USD ($)	Jun. 30, 2017 property	Jun. 30, 2016 USD ($) property
Dispositions of Income Properties
Impairment charges	$ 1,970,822			$ 2,180,730
2017 dispositions of income property subject to a lease \| Sold
Dispositions of Income Properties
Number of properties in the disposal group \| property			0
2016 dispositions of income property subject to a lease \| Sold
Dispositions of Income Properties
Number of properties in the disposal group \| property	1			4
Impairment charges				$ 210,000
2016 dispositions of income property subject to a lease \| Under contract to be sold
Dispositions of Income Properties
Number of properties in the disposal group \| property				14
Impairment charges	$ 942,000	$ 210,000		$ 942,000
Impairment write-down	$ (783,000)	$ (134,000)