Income taxes - Schedule of Estimated Net Operating Losses (NOLs) (Details)	Jun. 30, 2020 USD ($)
Income Tax Disclosure [Line Items]
Federal	$ 30,486,000
State	26,140,000
InterGroup [Member]
Income Tax Disclosure [Line Items]
Federal
State
Santa Fe [Member]
Income Tax Disclosure [Line Items]
Federal	9,781,000
State	4,761,000
Portsmouth [Member]
Income Tax Disclosure [Line Items]
Federal	20,705,000
State	$ 21,379,000

Amount before allocation of valuation allowances of deferred tax asset attributable to deductible domestic operating loss carryforwards. Excludes state and local operating loss carryforwards.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32632-109319

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32621-109319

Name:	us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsDomestic
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant