Annual report pursuant to Section 13 and 15(d)

Unsecured Lines Of Credit Payable - Lines Of Credit Unused and Available (Details)

v2.4.1.9
Unsecured Lines Of Credit Payable - Lines Of Credit Unused and Available (Details) (USD $)
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Jan. 23, 2015
Line of Credit Facility [Line Items]        
Line of Credit Facility, Commitment Fee Amount $ 1,267,000us-gaap_LineOfCreditFacilityCommitmentFeeAmount $ 1,267,000us-gaap_LineOfCreditFacilityCommitmentFeeAmount $ 1,062,000us-gaap_LineOfCreditFacilityCommitmentFeeAmount  
Committed capacity 500,000,000us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity 500,000,000us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity 500,000,000us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity  
Borrowings outstanding (50,000,000)us-gaap_LineOfCredit 0us-gaap_LineOfCredit 0us-gaap_LineOfCredit  
Letters of Credit Outstanding, Amount 0us-gaap_LettersOfCreditOutstandingAmount 0us-gaap_LettersOfCreditOutstandingAmount    
Credit Facility No. 1 [Member]        
Line of Credit Facility [Line Items]        
Committed capacity 100,000,000us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
/ us-gaap_LineOfCreditFacilityAxis
= wre_CreditFacilityNo1Member
     
Borrowings outstanding (5,000,000)us-gaap_LineOfCredit
/ us-gaap_LineOfCreditFacilityAxis
= wre_CreditFacilityNo1Member
0us-gaap_LineOfCredit
/ us-gaap_LineOfCreditFacilityAxis
= wre_CreditFacilityNo1Member
   
Letters of Credit Outstanding, Amount 0us-gaap_LettersOfCreditOutstandingAmount
/ us-gaap_LineOfCreditFacilityAxis
= wre_CreditFacilityNo1Member
     
Unused and available 95,000,000us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity
/ us-gaap_LineOfCreditFacilityAxis
= wre_CreditFacilityNo1Member
     
Credit Facility No. 2 [Member]        
Line of Credit Facility [Line Items]        
Committed capacity 400,000,000us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
/ us-gaap_LineOfCreditFacilityAxis
= wre_CreditFacilityNo2Member
     
Borrowings outstanding (45,000,000)us-gaap_LineOfCredit
/ us-gaap_LineOfCreditFacilityAxis
= wre_CreditFacilityNo2Member
0us-gaap_LineOfCredit
/ us-gaap_LineOfCreditFacilityAxis
= wre_CreditFacilityNo2Member
   
Letters of Credit Outstanding, Amount 0us-gaap_LettersOfCreditOutstandingAmount
/ us-gaap_LineOfCreditFacilityAxis
= wre_CreditFacilityNo2Member
     
Unused and available 355,000,000us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity
/ us-gaap_LineOfCreditFacilityAxis
= wre_CreditFacilityNo2Member
     
Credit Facility Accordion Feature [Member] | Credit Facility No. 1 [Member]        
Line of Credit Facility [Line Items]        
Committed capacity 200,000,000us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
/ us-gaap_LineOfCreditFacilityAxis
= wre_CreditFacilityNo1Member
/ us-gaap_StatementScenarioAxis
= wre_CreditFacilityAccordionFeatureMember
     
Credit Facility Accordion Feature [Member] | Credit Facility No. 2 [Member]        
Line of Credit Facility [Line Items]        
Committed capacity 600,000,000us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
/ us-gaap_LineOfCreditFacilityAxis
= wre_CreditFacilityNo2Member
/ us-gaap_StatementScenarioAxis
= wre_CreditFacilityAccordionFeatureMember
     
Subsequent Event [Member] | Credit Facility No. 2 [Member]        
Line of Credit Facility [Line Items]        
Letters of Credit Outstanding, Amount       $ 15,500,000us-gaap_LettersOfCreditOutstandingAmount
/ us-gaap_LineOfCreditFacilityAxis
= wre_CreditFacilityNo2Member
/ us-gaap_SubsequentEventTypeAxis
= us-gaap_SubsequentEventMember