Equity method investment summarized financial information debt.

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- Definition

Estimated potential additional contribution obligation.

+ References

No definition available.

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- Definition

Estimated redevelopment costs.

+ References

No definition available.

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- Definition

Excess estimated ground lease funding.

+ References

No definition available.

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- Definition

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

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- Definition

For transactions that are recognized separately from the acquisition of assets and assumptions of liabilities in the business combination, such as related to pre-existing relationships with the acquiree, this element represents the disclosure of the amount of acquisition related costs.

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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

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

Term of lessee's operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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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.

+ Details

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- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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- Definition

The cash outflow for acquisition of or capital improvements to properties held for investment (operating, managed, leased) or for use.

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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 (Textual) (Details) - USD ($)		3 Months Ended
	Apr. 02, 2015	Mar. 31, 2019	Dec. 31, 2018	Oct. 13, 2017
Property Subject to or Available for Operating Lease [Line Items]
Loan outstanding principal balance		$ 2,094,797,000	$ 2,028,046,000
4040 Wilson Venture [Member]
Property Subject to or Available for Operating Lease [Line Items]
Guarantees, maximum exposure amount		41,300,000
Loan outstanding principal balance		150,000,000.0
Unconsolidated Real Estate Ventures [Member]
Property Subject to or Available for Operating Lease [Line Items]
Real estate ventures aggregate indebtedness		498,200,000
PJP VII [Member]
Property Subject to or Available for Operating Lease [Line Items]
Guarantees, maximum exposure amount		300,000
Loan outstanding principal balance		3,700,000
618 Market Street [Member]
Property Subject to or Available for Operating Lease [Line Items]
Contingent consideration, liability	$ 2,000,000.0	1,900,000
Fair value of contingent consideration	1,600,000
Interest expense	$ 2,000,000.0
The Bulletin Building [Member]
Property Subject to or Available for Operating Lease [Line Items]
Funding requirement met for capital improvements		1,700,000
Expected excess redevelopment funding		37,300,000
Estimated aggregate cost		83,100,000
Acquisition cost, inclusive in estimated aggregate cost				$ 37,800,000
Drexel Square [Member]
Property Subject to or Available for Operating Lease [Line Items]
Required spending in capital improvements to property		2,700,000
Estimated potential additional contribution obligation		$ 600,000
Minimum [Member]
Property Subject to or Available for Operating Lease [Line Items]
Lease terms		10 years
Minimum [Member] \| The Bulletin Building [Member]
Property Subject to or Available for Operating Lease [Line Items]
Required spending in capital improvements to property		$ 8,000,000.0
Maximum [Member]
Property Subject to or Available for Operating Lease [Line Items]
Lease terms		66 years
Mortgage Lenders [Member]
Property Subject to or Available for Operating Lease [Line Items]
Associated letter of credit		$ 0