Sale of Air Rights (Details) - Downtown Atlanta $ in Thousands	Feb. 26, 2019 USD ($) a
Real Estate [Line Items]
Area of property (in acres) \| a	8
Gross sales price of investment properties	$ 13,250
Gain on sale of investment properties	$ 13,100

This element represents the amount of gain (loss) on sale of properties during the reporting period gross of the applicable income taxes realized.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 974
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-15.(a)(1)(ii)
-URI http://asc.fasb.org/extlink&oid=6875705&loc=d3e641549-123027

Name:	us-gaap_GainLossOnSaleOfPropertiesBeforeApplicableIncomeTaxes
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration