Represents the number of office properties sold.

No definition available.

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Namespace Prefix:	fsp_
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Balance Type:	na
Period Type:	instant

- Definition

Represents the number of unrelated purchasers of properties.

+ References

No definition available.

+ Details

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Namespace Prefix:	fsp_
Data Type:	xbrli:integerItemType
Balance Type:	na
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- Definition

Aggregate dividends declared during the period for each share of common stock outstanding.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480008/505-10-S99-1

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

The cash inflow from the sale of formerly productive land held for sale, anything permanently fixed to it, including buildings, structures on it, and so forth.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 12
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482740/230-10-45-12

+ Details

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

- Definition

Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 830
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481674/830-30-50-2

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 855
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483399/855-10-50-2

+ Details

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Subsequent Events (Details) $ / shares in Units, $ in Millions		1 Months Ended		3 Months Ended
	Jul. 07, 2023 $ / shares	Jul. 31, 2023 USD ($) property entity	Dec. 31, 2021 $ / shares	Jun. 30, 2023 $ / shares	Mar. 31, 2023 $ / shares	Jun. 30, 2022 $ / shares	Mar. 31, 2022 $ / shares
Subsequent Events
Cash dividend declared per share (in dollars per share)			$ 0.32	$ 0.01	$ 0.01	$ 0.09	$ 0.09
Subsequent event
Subsequent Events
Cash dividend declared per share (in dollars per share)	$ 0.01
Number of unrelated purchasers \| entity		3
Number of properties sold \| property		3
Sale price \| $		$ 156