The charge against earnings in the period to reduce the carrying amount of real property to fair value.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123570139&loc=d3e3602-108585

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109226691&loc=d3e2921-110230

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

Impairment Charges (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
Impairment Charges (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Real Estate Properties [Line Items]
Impairment charge	$ 0	$ 3,642	$ 520	$ 3,642
Unconsolidated Joint Ventures
Real Estate Properties [Line Items]
Impairment charge	$ 0	$ 0	2,813	$ 0
Unconsolidated Joint Ventures \| St. Louis, MO
Real Estate Properties [Line Items]
Impairment charge			$ 520