Name:	gov_AggregateNetBookValueOfRealEstatePropertiesCollateralized
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Period Type:	instant

The aggregate principal amount on real estate properties serving as collateral for debt as of the balance sheet date.

No definition available.

Name:	gov_AggregatePrincipalAmountOfRealEstatePropertiesCollateralized
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Balance Type:	credit
Period Type:	instant

The option to extend the maturity date subject to certain conditions and the payment of a fee under the credit facility.

No definition available.

Name:	gov_DebtInstrumentContingentOptionToExtendMaturityDate
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Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Represents the number of mortgage loans on real estate assumed in acquisitions during the period.

No definition available.

Name:	gov_MortgageLoansOnRealEstateAssumedInAcquisitionsNumberOfLoans
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Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

The number of buildings serving as collateral for debt as of the balance sheet date.

No definition available.

Name:	gov_NumberOfBuildingsCollateralized
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Balance Type:	na
Period Type:	instant

Number Of Joint Ventures

No definition available.

Name:	gov_NumberOfJointVentures
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Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

Number Of Mortgage Notes Securing Joint Ventures

No definition available.

Name:	gov_NumberOfMortgageNotesSecuringJointVentures
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Balance Type:	na
Period Type:	duration

Represents the number of real estate properties serving as a collateral for debt, as of the balance sheet date.

No definition available.

Name:	gov_NumberOfRealEstatePropertiesCollateralized
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Balance Type:	na
Period Type:	instant

Represents the net amount of the notes issued.

No definition available.

Name:	gov_SeniorUnsecuredNotesNetOfOfferingExpenses
Namespace Prefix:	gov_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Represents the underwriters option to purchase additional notes.

No definition available.

Name:	gov_UnderwriterOptionExerciseAmount
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Represents the calculation of the average interest rate weighted by the amount of long-term debt outstanding by type or by instrument at that time.

No definition available.

Name:	gov_WeightedAverageAnnualInterestRate
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Balance Type:	na
Period Type:	duration

Amount of long-term debt due after one year or the normal operating cycle, if longer, assumed at the acquisition date.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Period Type:	instant

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

No definition available.

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Data Type:	num:percentItemType
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Period Type:	duration

Face (par) amount of debt instrument at time of issuance.

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Name:	us-gaap_DebtInstrumentFaceAmount
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

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

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

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.

No definition available.

Name:	us-gaap_DebtInstrumentLineItems
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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

No definition available.

Name:	us-gaap_DebtInstrumentTerm
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Balance Type:	na
Period Type:	duration

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

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

Gross amount of debt extinguished.

No definition available.

Name:	us-gaap_ExtinguishmentOfDebtAmount
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Balance Type:	debit
Period Type:	duration

Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Period Type:	duration

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Name:	us-gaap_LineOfCredit
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

The fee, expressed as a percentage of the line of credit facility, for the line of credit facility regardless of whether the facility has been used.

No definition available.

Name:	us-gaap_LineOfCreditFacilityCommitmentFeePercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

No definition available.

Name:	us-gaap_LongTermDebtFairValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

The cash inflow during the period from additional borrowings in aggregate debt. Includes proceeds from short-term and long-term debt.

No definition available.

Name:	us-gaap_ProceedsFromIssuanceOfDebt
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

The cash outflow during the period from the repayment of aggregate short-term and long-term debt. Excludes payment of capital lease obligations.

No definition available.

Name:	us-gaap_RepaymentsOfDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Including the current and noncurrent portions, carrying value as of the balance sheet date of uncollateralized debt obligations (with maturities initially due after one year or beyond the operating cycle if longer).

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Name:	us-gaap_UnsecuredDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Name:	us-gaap_DebtInstrumentAxis=gov_UnsecuredDebtDueIn2020Member
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Name:	us-gaap_DebtInstrumentAxis=gov_UnsecuredDebtDueIn2022Member
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Name:	us-gaap_DebtInstrumentAxis=gov_A4SeniorUnsecuredNotesDue2022Member
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Name:	us-gaap_CreditFacilityAxis=us-gaap_LineOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
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Name:	us-gaap_CreditFacilityAxis=us-gaap_LongTermDebtMember
Namespace Prefix:
Data Type:	na
Balance Type:
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Name:	us-gaap_CreditFacilityAxis=us-gaap_SeniorNotesMember
Namespace Prefix:
Data Type:	na
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Name:	us-gaap_CreditFacilityAxis=us-gaap_LetterOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
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Name:	us-gaap_DebtInstrumentAxis=gov_BridgeLoanFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
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Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix:
Data Type:	na
Balance Type:
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Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_SeniorNotesMember
Namespace Prefix:
Data Type:	na
Balance Type:
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Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_MortgagesMember
Namespace Prefix:
Data Type:	na
Balance Type:
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Name:	us-gaap_DebtInstrumentAxis=gov_MortgageNote6.21PercentDueIn2016Member
Namespace Prefix:
Data Type:	na
Balance Type:
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Name:	us-gaap_DebtInstrumentAxis=gov_MortgageNote5.55PercentDueIn2016Member
Namespace Prefix:
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Name:	us-gaap_BusinessAcquisitionAxis=gov_FirstPotomacRealtyTrustMember
Namespace Prefix:
Data Type:	na
Balance Type:
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Name:	us-gaap_DebtInstrumentAxis=gov_FPOMortgageMember
Namespace Prefix:
Data Type:	na
Balance Type:
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Name:	us-gaap_DebtInstrumentAxis=gov_JointVentureMortgageMember
Namespace Prefix:
Data Type:	na
Balance Type:
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Name:	dei_LegalEntityAxis=gov_FirstPotomacRealtyTrustMember
Namespace Prefix:
Data Type:	na
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Name:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=gov_JointVentureProperty1Member
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Name:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=gov_JointVentureProperty2Member
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