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

No definition available.

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Period Type:	duration

- 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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Period Type:	duration

- Definition

Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

+ References

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

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.

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

The number of derivative instruments of a particular group held by the entity.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5580258-113959

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5579245-113959

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Period Type:	instant

- Definition

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.

+ References

No definition available.

+ Details

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

- Definition

The effective interest rate during the reporting period.

+ References

+ Details

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

- 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

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

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.

+ References

+ Details

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

- Definition

The carrying value as of the balance sheet date of the noncurrent portion 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.

+ References

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)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section 45
-Paragraph 13
-URI http://asc.fasb.org/extlink&oid=28361426&loc=d3e1314-112600

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section 45
-Paragraph 14
-URI http://asc.fasb.org/extlink&oid=28361426&loc=d3e1336-112600

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Line-of-Credit Arrangement
-URI http://asc.fasb.org/extlink&oid=6517033

+ Details

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

- Definition

Line of Credit Facility, extension period

+ References

No definition available.

+ Details

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Namespace Prefix:	wre_
Data Type:	us-types:durationStringItemType
Balance Type:	na
Period Type:	duration

- Definition

line of credit facility, number of extensions allowed

+ References

No definition available.

+ Details

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- Details

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- Details

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- Details

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- Details

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- Details

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- Details

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Unsecured Lines of Credit Payable - Narrative (Details)	3 Months Ended
Unsecured Lines of Credit Payable - Narrative (Details)	Mar. 31, 2017 USD ($)	Sep. 30, 2015 USD ($)
Line of Credit
Line of Credit Facility [Line Items]
Line of Credit Facility, Commitment Fee Percentage	0.20%
Line of Credit Facility, Interest Rate During Period	1.00%
Revolving Credit Facility
Line of Credit Facility [Line Items]
Committed capacity	$ 1,000,000,000.0
Revolving Credit Facility \| 2015 Term Loan [Member]
Line of Credit Facility [Line Items]
Long-term Line of Credit, Noncurrent		$ 150,000,000
Debt Instrument, Term	5 years 6 months
Revolving Credit Facility \| Line of Credit
Line of Credit Facility [Line Items]
Committed capacity	$ 600,000,000
Debt Instrument, Maturity Date	Jun. 22, 2019
line of credit facility, number of extensions allowed	2
Line of Credit Facility, extension period	6 months
Minimum [Member] \| Line of Credit
Line of Credit Facility [Line Items]
Line of Credit Facility, Commitment Fee Percentage	0.125%
Maximum [Member] \| Line of Credit
Line of Credit Facility [Line Items]
Line of Credit Facility, Commitment Fee Percentage	0.30%
London Interbank Offered Rate (LIBOR) [Member] \| 2015 Term Loan [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Description of Variable Rate Basis	P1M
London Interbank Offered Rate (LIBOR) [Member] \| Line of Credit
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.00%
London Interbank Offered Rate (LIBOR) [Member] \| Revolving Credit Facility \| 2015 Term Loan [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.10%
London Interbank Offered Rate (LIBOR) [Member] \| Minimum [Member] \| Line of Credit
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.875%
London Interbank Offered Rate (LIBOR) [Member] \| Maximum [Member] \| Line of Credit
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.55%
Base Rate [Member] \| Minimum [Member] \| Line of Credit
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.00%
Base Rate [Member] \| Maximum [Member] \| Line of Credit
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.55%
Federal Funds Effective Swap Rate [Member] \| Line of Credit
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.50%
Interest Rate Swap [Member] \| 2015 Term Loan [Member]
Line of Credit Facility [Line Items]
Derivative, Number of Instruments Held	2