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No definition available.

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- Definition

Company agreed not to sell acquired properties up to the period.

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No definition available.

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Equity method investment summarized financial information debt.

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- Definition

Estimated potential additional contribution obligation.

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No definition available.

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- Definition

Leased area of building.

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No definition available.

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- Definition

Tax guarantee obligation

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No definition available.

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- Definition

Area of land held.

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No definition available.

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- Definition

Amount of liabilities incurred by the acquirer as part of consideration transferred in a business combination.

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- Definition

Amount of liability recognized arising from contingent consideration in a business combination.

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- Definition

Fair value at acquisition-date of the equity interest in the acquiree held by the acquirer, immediately before the acquisition date for businesses combined in stages.

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- Definition

Amount of contractual obligation, including but not limited to, long-term debt, capital lease obligations, operating lease obligations, purchase obligations, and other commitments.

+ References

No definition available.

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- Definition

Amount of unused borrowing capacity under the long-term financing arrangement that is available to the entity as of the balance sheet date.

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- Definition

Maximum potential amount of future payments (undiscounted) the guarantor could be required to make under the guarantee or each group of similar guarantees before reduction for potential recoveries under recourse or collateralization provisions.

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- Definition

Amount of the cost of borrowed funds accounted for as interest expense.

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- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

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- Definition

The equity interest of noncontrolling shareholders, partners or other equity holders in consolidated entity.

+ References

No definition available.

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- Definition

Net rentable area for properties owned.

+ References

No definition available.

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- Definition

Cash outflow related to amounts given in advance to show or confirm an intention to complete an acquisition of land, buildings, other structures, or any item classified as real estate.

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- Definition

The cash outflow for acquisition of buildings (properties) whether for investment or use.

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The cash outflow from the acquisition of real estate intended to generate income for the owner; excludes land acquired for use by the owner.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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COMMITMENTS AND CONTINGENCIES - Narrative (Details)		1 Months Ended	12 Months Ended
COMMITMENTS AND CONTINGENCIES - Narrative (Details)	Apr. 02, 2015 USD ($)	Sep. 30, 2004 USD ($)	Dec. 31, 2019 USD ($) a ft²	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Property Subject to or Available for Operating Lease [Line Items]
Real estate ventures aggregate indebtedness			$ 596,007,000	$ 370,319,000
Agreed holding period (not to sell) for properties acquired as part of the TRC acquisition			15 years
Prentiss Properties Trust \| Commerce Square
Property Subject to or Available for Operating Lease [Line Items]
Non-controlling interest, ownership percentage by non-controlling Owners			1.00%
618 Market Street
Property Subject to or Available for Operating Lease [Line Items]
Contingent consideration, liability	$ 2,000,000.0		$ 1,970,000
Fair value of contingent consideration	1,600,000
Interest expense	$ 2,000,000.0
Drexel Square
Property Subject to or Available for Operating Lease [Line Items]
Required spending in capital improvements to property			8,500,000
Estimated potential additional contribution obligation			$ 2,800,000
Two Logan Square
Property Subject to or Available for Operating Lease [Line Items]
Leased area of building \| ft²			708,844
Amount to be paid if the Company takes fee title to Two Logan Square upon foreclosure of related mortgage			$ 2,900,000
Liability related to acquisition of TRC		$ 700,000	2,900,000
One Commerce Square
Property Subject to or Available for Operating Lease [Line Items]
Tax guarantee obligation			125,000,000.0
Two Commerce Square
Property Subject to or Available for Operating Lease [Line Items]
Tax guarantee obligation			100,000,000.0
Mortgage Lenders
Property Subject to or Available for Operating Lease [Line Items]
Associated letter of credit			0
Unconsolidated Real Estate Ventures
Property Subject to or Available for Operating Lease [Line Items]
Real estate ventures aggregate indebtedness			596,007,000
4040 Wilson Venture
Property Subject to or Available for Operating Lease [Line Items]
Real estate ventures aggregate indebtedness			114,845,000	$ 57,288,000
Secured construction loan with total borrowing capacity					$ 150,000,000.0
4040 Wilson Venture \| 4040 Wilson Venture
Property Subject to or Available for Operating Lease [Line Items]
Secured construction loan with total borrowing capacity			150,000,000.0
Guarantees, maximum exposure amount			$ 41,300,000
Radnor PA Property
Property Subject to or Available for Operating Lease [Line Items]
Rentable square feet \| ft²			170,000
Acres \| a			7.8
Building purchase price			$ 20,300,000
Land purchase price			11,300,000
Payments for deposit on real estate investment			$ 1,000,000