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

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-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

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- 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.

+ Details

Name:	us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Carrying value as of the balance sheet date, including the current and noncurrent portions, of collateralized debt obligations (with maturities initially due after one year or beyond the operating cycle, if longer). Such obligations include mortgage loans, chattel loans, and any other borrowings secured by assets of the borrower.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-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

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-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=6879938&loc=d3e572229-122910

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 19, 20, 22
-Article 5

+ Details

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

- Definition

Including the current and noncurrent portions, carrying value as of the balance sheet date of Notes with the highest claim on the assets of the issuer in case of bankruptcy or liquidation (with maturities initially due after one year or beyond the operating cycle if longer). Senior note holders are paid off in full before any payments are made to junior note holders.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.16(a))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-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

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

- Details

Name:	us-gaap_DebtInstrumentAxis=gov_SeniorSecuredNote3.75PercentDueIn2019Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=gov_MortgageNote5.55PercentDueIn2016Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=gov_MortgageNote6.21PercentDueIn2016Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=gov_MortgageNote5.88PercentDueIn2021Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=gov_MortgageNote7PercentDueIn2019Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=gov_MortgageNote8.15PercentDueIn2021Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=gov_MortgageNote5.73PercentDueIn2015Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByMeasurementBasisAxis=us-gaap_CarryingReportedAmountFairValueDisclosureMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByMeasurementBasisAxis=us-gaap_EstimateOfFairValueFairValueDisclosureMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Fair Value of Assets and Liabilities (Details) - USD ($) $ in Thousands	Feb. 29, 2016	Jan. 31, 2016	Dec. 31, 2015	Jul. 31, 2015	Dec. 31, 2014
Fair Value of Financial Instruments
Mortgage notes payable, net			$ 136,643		$ 187,694
Senior Notes			347,981		347,423
Interest rate (as a percent)	6.21%	5.55%		5.73%
3.75% Senior unsecured note due In 2019
Fair Value of Financial Instruments
Senior Notes			$ 347,981		347,423
Interest rate (as a percent)			3.75%
5.55% Mortgage notes due in 2016
Fair Value of Financial Instruments
Mortgage notes payable, net			$ 83,441		85,167
Interest rate (as a percent)			5.55%
6.21% Mortgage notes due in 2016
Fair Value of Financial Instruments
Mortgage notes payable, net			$ 23,499		23,833
Interest rate (as a percent)			6.21%
5.88% Mortgage notes due in 2021
Fair Value of Financial Instruments
Mortgage notes payable, net			$ 14,160		14,374
Interest rate (as a percent)			5.88%
7% Mortgage notes due in 2019
Fair Value of Financial Instruments
Mortgage notes payable, net			$ 9,199		9,563
Interest rate (as a percent)			7.00%
8.15% Mortgage notes due in 2021
Fair Value of Financial Instruments
Mortgage notes payable, net			$ 6,344		7,339
Interest rate (as a percent)			8.15%
5.73% Mortgage notes due in 2015
Fair Value of Financial Instruments
Mortgage notes payable, net					47,418
Interest rate (as a percent)			5.73%
Carrying Amount
Fair Value of Financial Instruments
Mortgage notes payable, net			$ 484,624		535,117
Carrying Amount \| 3.75% Senior unsecured note due In 2019
Fair Value of Financial Instruments
Senior Notes			347,981		347,423
Carrying Amount \| 5.55% Mortgage notes due in 2016
Fair Value of Financial Instruments
Mortgage notes payable, net			83,441		85,167
Carrying Amount \| 6.21% Mortgage notes due in 2016
Fair Value of Financial Instruments
Mortgage notes payable, net			23,499		23,833
Carrying Amount \| 5.88% Mortgage notes due in 2021
Fair Value of Financial Instruments
Mortgage notes payable, net			14,160		14,374
Carrying Amount \| 7% Mortgage notes due in 2019
Fair Value of Financial Instruments
Mortgage notes payable, net			9,199		9,563
Carrying Amount \| 8.15% Mortgage notes due in 2021
Fair Value of Financial Instruments
Mortgage notes payable, net			6,344		7,339
Carrying Amount \| 5.73% Mortgage notes due in 2015
Fair Value of Financial Instruments
Mortgage notes payable, net					47,418
Fair Value
Fair Value of Financial Instruments
Mortgage notes payable, net			490,221		548,407
Fair Value \| 3.75% Senior unsecured note due In 2019
Fair Value of Financial Instruments
Senior Notes			351,692		356,129
Fair Value \| 5.55% Mortgage notes due in 2016
Fair Value of Financial Instruments
Mortgage notes payable, net			83,457		85,171
Fair Value \| 6.21% Mortgage notes due in 2016
Fair Value of Financial Instruments
Mortgage notes payable, net			24,038		25,394
Fair Value \| 5.88% Mortgage notes due in 2021
Fair Value of Financial Instruments
Mortgage notes payable, net			14,678		15,249
Fair Value \| 7% Mortgage notes due in 2019
Fair Value of Financial Instruments
Mortgage notes payable, net			9,645		10,275
Fair Value \| 8.15% Mortgage notes due in 2021
Fair Value of Financial Instruments
Mortgage notes payable, net			$ 6,711		7,956
Fair Value \| 5.73% Mortgage notes due in 2015
Fair Value of Financial Instruments
Mortgage notes payable, net					$ 48,233