Variable Interest Entity - Narrative (Details) $ / shares in Units, $ in Millions	Sep. 30, 2019	Dec. 08, 2016 USD ($) property subsidiary $ / shares
Pillarstone OP [Member]
Schedule of Equity Method Investments [Line Items]
Ownership percentage		18.60%
Accrued rents and accounts receivable, net of allowance for doubtful accounts		$ 4.1
Conversion ratio, LTIP units to OP units (in shares)	1
Conversion ratio, OP units to common shares (in shares)	1
Whitestone [Member] | Variable Interest Entity
Schedule of Equity Method Investments [Line Items]
Number of wholly-owned subsidiaries contributed to variable interest entity | subsidiary		4
Number of non-core properties contributed to variable interest entity | property		14
Consideration amount		$ 84.0
Consideration, limited partnership interest		$ 18.1
Consideration, limited partnership interest (in dollars per share) | $ / shares		$ 1.331
Liabilities assumed		$ 65.9