Real Estate - Dispositions (Details) ft² in Thousands, $ in Thousands	1 Months Ended	12 Months Ended
	Sep. 30, 2023 USD ($) a	Dec. 31, 2021 USD ($) ft² property	Jul. 31, 2021 USD ($) a
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of office properties sold | property		3
Disposal Group, Disposed of by Sale, Not Discontinued Operations | 816 Congress | Austin, TX
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Square Feet | ft²		435
Sales Price		$ 174,000
Gain on Sale, Net		$ 77,200
Disposal Group, Disposed of by Sale, Not Discontinued Operations | One South at the Plaza | Charlotte, NC
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Square Feet | ft²		891
Sales Price		$ 271,500
Gain on Sale, Net		$ 12,700
Disposal Group, Disposed of by Sale, Not Discontinued Operations | Burnett Plaza | Fort Worth
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Square Feet | ft²		1,000
Sales Price		$ 137,500
Gain on Sale, Net		200
Disposal Group, Disposed of by Sale, Not Discontinued Operations | Atlanta Land
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Square Feet | a	10.4
Sales Price	$ 4,250
Gain on Sale, Net	$ 507
Disposal Group, Disposed of by Sale, Not Discontinued Operations | 100 Mill - Adjacent Land
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Square Feet | a			0.7
Sales Price			$ 6,400
Gain on Sale, Net		$ 90,100