Extension Option (in years)

No definition available.

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- Definition

Leased percentage

+ References

No definition available.

+ Details

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- Definition

Lessor Operating Lease Lease Not Yet Commenced Leased SF

+ References

No definition available.

+ Details

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- Definition

Number of extensions

+ References

No definition available.

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- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

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- Definition

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=109500613&loc=SL6031897-161870

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(16))
-URI http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

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- Definition

The reference rate for the variable rate of the debt instrument, such as LIBOR or the US Treasury rate and the maturity of the reference rate used, such as three months or six months LIBOR.

+ References

No definition available.

+ Details

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- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=114001798&loc=d3e33918-111571

+ Details

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- Definition

Description of lessor's operating lease that has not yet commenced.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 30
-Section 50
-Paragraph 3
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=119202524&loc=SL77919359-209981

+ Details

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- Definition

Term of lessor's operating lease not yet commenced, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 30
-Section 50
-Paragraph 3
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=119202524&loc=SL77919359-209981

+ Details

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- Definition

Net rentable area for properties owned.

+ References

No definition available.

+ Details

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- 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

No definition available.

+ Details

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Subsequent Events (Details) $ in Millions	Nov. 03, 2020 ft²	Oct. 30, 2020 USD ($) yr	Jun. 09, 2020 USD ($) ft² yr	Oct. 01, 2020 ft²	Sep. 30, 2020 USD ($) ft²	Jun. 08, 2020 USD ($)
Subsequent Event [Member] \| 200 West Street
Subsequent Event [Line Items]
Lessor, Operating Lease, Lease Not yet Commenced, Description	approximately 138,000 square-foot, 10-year lease with a new tenant at 200 West Street in Waltham, Massachusetts
Lessor Operating Lease Lease Not Yet Commenced Leased SF	138,000
Lessor, Operating Lease, Lease Not yet Commenced, Term of Contract	10 years
Leased percentage	100.00%
Dock 72 [Member] \| Subsequent Event [Member]
Subsequent Event [Line Items]
Ownership Percentage				50.00%
Net Rentable Area (in sf)				670,000
Market Square North [Member]
Subsequent Event [Line Items]
Ownership Percentage					50.00%
Net Rentable Area (in sf)					418,000
Debt \| $					$ 114.2
Debt Instrument, Interest Rate, Stated Percentage					4.85%
Market Square North [Member] \| Subsequent Event [Member]
Subsequent Event [Line Items]
Ownership Percentage		50.00%
Debt \| $		$ 125.0			$ 114.2
Debt Instrument, Interest Rate, Stated Percentage					4.85%
Number of extensions		1
Extension Option (in years) \| yr		1
Debt Instrument, Basis Spread on Variable Rate		2.30%
Market Square North [Member] \| Subsequent Event [Member] \| Base Rate [Member]
Subsequent Event [Line Items]
Debt Instrument, Description of Variable Rate Basis		greater of (x) LIBOR or (y) 0.50%
Metropolitan Square Associates Llc [Member]
Subsequent Event [Line Items]
Ownership Percentage			20.00%
Net Rentable Area (in sf)			654,000
Debt \| $			$ 288.0			$ 155.9
Debt Instrument, Interest Rate, Stated Percentage						5.75%
Number of extensions			2
Extension Option (in years) \| yr			1
Debt Instrument, Basis Spread on Variable Rate			4.75%
Metropolitan Square Associates Llc [Member] \| Base Rate [Member]
Subsequent Event [Line Items]
Debt Instrument, Description of Variable Rate Basis			the greater of (x) LIBOR or (y) 0.65%