XML 66 R72.htm IDEA: XBRL DOCUMENT v2.4.1.9
Indebtedness - Schedule of Outstanding Indebtedness (Details) (USD $)
In Thousands, unless otherwise specified
Dec. 31, 2014
Dec. 31, 2013
Debt Instrument [Line Items]    
Outstanding indebtedness $ 2,201,537us-gaap_DebtInstrumentCarryingAmount $ 2,986,211us-gaap_DebtInstrumentCarryingAmount
Unamortized net premiums and discounts 6,128us-gaap_DebtInstrumentUnamortizedDiscountPremiumNet 19,199us-gaap_DebtInstrumentUnamortizedDiscountPremiumNet
Total 2,207,665us-gaap_LongTermDebt 3,005,410us-gaap_LongTermDebt
Unsecured Revolving Credit Facility, due October 2015    
Debt Instrument [Line Items]    
Interest rate stated percentage 1.669%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= us-gaap_LineOfCreditMember		  
Outstanding indebtedness 0us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= us-gaap_LineOfCreditMember		 235,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= us-gaap_LineOfCreditMember
Unsecured Term Loan, due December 2016    
Debt Instrument [Line Items]    
Interest rate stated percentage 2.019%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= eqc_UnsecuredTermLoanDueDecember2016Member		  
Outstanding indebtedness 400,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= eqc_UnsecuredTermLoanDueDecember2016Member		 500,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= eqc_UnsecuredTermLoanDueDecember2016Member
Unsecured Floating Rate Debt    
Debt Instrument [Line Items]    
Interest rate stated percentage 2.019%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= eqc_UnsecuredFloatingRateDebtMember		  
Outstanding indebtedness 400,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= eqc_UnsecuredFloatingRateDebtMember		 735,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= eqc_UnsecuredFloatingRateDebtMember
Senior Notes, due 2015 at 6.40%    
Debt Instrument [Line Items]    
Interest rate stated percentage 0.00%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= eqc_SeniorNotesSixPointFourZeroPercentDue2015Member		  
Outstanding indebtedness 0us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= eqc_SeniorNotesSixPointFourZeroPercentDue2015Member		 33,440us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= eqc_SeniorNotesSixPointFourZeroPercentDue2015Member
Senior Notes, due 2015 at 5.75%    
Debt Instrument [Line Items]    
Interest rate stated percentage 5.75%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= eqc_SeniorNotesFivePointSevenFivePercentDue2015Member		  
Outstanding indebtedness 138,773us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= eqc_SeniorNotesFivePointSevenFivePercentDue2015Member		 138,773us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= eqc_SeniorNotesFivePointSevenFivePercentDue2015Member
Senior Notes, due 2016 at 6.25%    
Debt Instrument [Line Items]    
Interest rate stated percentage 6.25%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= eqc_SeniorNotesSixPointTwoFivePercentDue2016Member		  
Outstanding indebtedness 139,104us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= eqc_SeniorNotesSixPointTwoFivePercentDue2016Member		 139,104us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= eqc_SeniorNotesSixPointTwoFivePercentDue2016Member
Senior Notes, due 2017 at 6.25%    
Debt Instrument [Line Items]    
Interest rate stated percentage 6.25%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= eqc_SeniorNotesSixPointTwoFivePercentDue2017Member		  
Outstanding indebtedness 250,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= eqc_SeniorNotesSixPointTwoFivePercentDue2017Member		 250,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= eqc_SeniorNotesSixPointTwoFivePercentDue2017Member
Senior Notes, due 2018 at 6.65%    
Debt Instrument [Line Items]    
Interest rate stated percentage 6.65%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= eqc_SeniorNotesSixPointSixFivePercentDue2018Member		  
Outstanding indebtedness 250,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= eqc_SeniorNotesSixPointSixFivePercentDue2018Member		 250,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= eqc_SeniorNotesSixPointSixFivePercentDue2018Member
Senior Notes, due 2019 at 7.50%    
Debt Instrument [Line Items]    
Interest rate stated percentage 0.00%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= eqc_SeniorNotesSevenPointFiveZeroPercentDue2019Member		  
Outstanding indebtedness 0us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= eqc_SeniorNotesSevenPointFiveZeroPercentDue2019Member		 125,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= eqc_SeniorNotesSevenPointFiveZeroPercentDue2019Member
Senior Notes, due 2020 at 5.875%    
Debt Instrument [Line Items]    
Interest rate stated percentage 5.875%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= eqc_SeniorNotesFivePointEightSevenFivePercentDue2020Member		  
Outstanding indebtedness 250,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= eqc_SeniorNotesFivePointEightSevenFivePercentDue2020Member		 250,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= eqc_SeniorNotesFivePointEightSevenFivePercentDue2020Member
Senior Notes, due 2042 at 5.75%    
Debt Instrument [Line Items]    
Interest rate stated percentage 5.75%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= eqc_SeniorNotesFivePointSevenFivePercentDue2042Member		  
Outstanding indebtedness 175,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= eqc_SeniorNotesFivePointSevenFivePercentDue2042Member		 175,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= eqc_SeniorNotesFivePointSevenFivePercentDue2042Member
Unsecured Fixed Rate Debt    
Debt Instrument [Line Items]    
Interest rate stated percentage 6.125%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= eqc_UnsecuredFixedRateDebtMember		  
Outstanding indebtedness 1,202,877us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= eqc_UnsecuredFixedRateDebtMember		 1,361,317us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= eqc_UnsecuredFixedRateDebtMember
Mortgage Notes Payable Encumbering 3920 Arkwright Road    
Debt Instrument [Line Items]    
Interest rate stated percentage 0.00%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= eqc_MortgageNotesPayableEncumbering3920ArkwrightRoadMember		  
Outstanding indebtedness 0us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= eqc_MortgageNotesPayableEncumbering3920ArkwrightRoadMember		 12,040us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= eqc_MortgageNotesPayableEncumbering3920ArkwrightRoadMember
Mortgage Notes Payable Encumbering 6200 Glenn Carlson Drive    
Debt Instrument [Line Items]    
Interest rate stated percentage 0.00%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= eqc_MortgageNotesPayableEncumbering6200GlennCarlsonDriveMember		  
Outstanding indebtedness 0us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= eqc_MortgageNotesPayableEncumbering6200GlennCarlsonDriveMember		 7,987us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= eqc_MortgageNotesPayableEncumbering6200GlennCarlsonDriveMember
Mortgage Notes Payable Encumbering 111 Monument Circle    
Debt Instrument [Line Items]    
Interest rate stated percentage 5.235%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= eqc_MortgageNotesPayableEncumbering111MonumentCircleMember		  
Outstanding indebtedness 116,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= eqc_MortgageNotesPayableEncumbering111MonumentCircleMember		 116,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= eqc_MortgageNotesPayableEncumbering111MonumentCircleMember
Mortgage Notes Payable Encumbering 225 Water Street    
Debt Instrument [Line Items]    
Interest rate stated percentage 6.03%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= eqc_MortgageNotesPayableEncumbering225WaterStreetMember		  
Outstanding indebtedness 40,059us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= eqc_MortgageNotesPayableEncumbering225WaterStreetMember		 40,334us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= eqc_MortgageNotesPayableEncumbering225WaterStreetMember
Mortgage Notes Payable Encumbering 111 East Wacker Drive    
Debt Instrument [Line Items]    
Interest rate stated percentage 6.29%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= eqc_MortgageNotesPayableEncumbering111EastWackerDriveMember		  
Outstanding indebtedness 142,666us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= eqc_MortgageNotesPayableEncumbering111EastWackerDriveMember		 144,522us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= eqc_MortgageNotesPayableEncumbering111EastWackerDriveMember
Mortgage Notes Payable Encumbering 2501 20th Place South    
Debt Instrument [Line Items]    
Interest rate stated percentage 7.36%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= eqc_MortgageNotesPayableEncumbering250120thPlaceSouthMember		  
Outstanding indebtedness 10,267us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= eqc_MortgageNotesPayableEncumbering250120thPlaceSouthMember		 10,804us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= eqc_MortgageNotesPayableEncumbering250120thPlaceSouthMember
Mortgage Notes Payable Encumbering Parkshore Plaza    
Debt Instrument [Line Items]    
Interest rate stated percentage 5.67%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= eqc_MortgageNotesPayableEncumberingParkshorePlazaMember		  
Outstanding indebtedness 41,275us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= eqc_MortgageNotesPayableEncumberingParkshorePlazaMember		 41,275us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= eqc_MortgageNotesPayableEncumberingParkshorePlazaMember
Mortgage Notes Payable Encumbering 600 West Chicago Avenue    
Debt Instrument [Line Items]    
Interest rate stated percentage 0.00%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= eqc_MortgageNotesPayableEncumbering600WestChicagoAvenueMember		  
Outstanding indebtedness 0us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= eqc_MortgageNotesPayableEncumbering600WestChicagoAvenueMember		 265,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= eqc_MortgageNotesPayableEncumbering600WestChicagoAvenueMember
Mortgage Notes Payable Encumbering 1735 Market Street    
Debt Instrument [Line Items]    
Interest rate stated percentage 5.66%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= eqc_MortgageNotesPayableEncumbering1735MarketStreetMember		  
Outstanding indebtedness 171,498us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= eqc_MortgageNotesPayableEncumbering1735MarketStreetMember		 173,247us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= eqc_MortgageNotesPayableEncumbering1735MarketStreetMember
Mortgage Notes Payable Encumbering 206 East 9th Street    
Debt Instrument [Line Items]    
Interest rate stated percentage 5.69%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= eqc_MortgageNotesPayableEncumbering206East9thStreetMember		  
Outstanding indebtedness 27,965us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= eqc_MortgageNotesPayableEncumbering206East9thStreetMember		 28,391us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= eqc_MortgageNotesPayableEncumbering206East9thStreetMember
Mortgage Notes Payable Encumbering 1320 Main Street    
Debt Instrument [Line Items]    
Interest rate stated percentage 5.30%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= eqc_MortgageNotesPayableEncumbering1320MainStreetMember		  
Outstanding indebtedness 38,979us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= eqc_MortgageNotesPayableEncumbering1320MainStreetMember		 39,598us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= eqc_MortgageNotesPayableEncumbering1320MainStreetMember
Mortgage Notes Payable Encumbering 33 Stiles Lane    
Debt Instrument [Line Items]    
Interest rate stated percentage 6.75%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= eqc_MortgageNotesPayableEncumbering33StilesLaneMember		  
Outstanding indebtedness 3,132us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= eqc_MortgageNotesPayableEncumbering33StilesLaneMember		 3,456us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= eqc_MortgageNotesPayableEncumbering33StilesLaneMember
Mortgage Notes Payable Encumbering 97 Newberry Road    
Debt Instrument [Line Items]    
Interest rate stated percentage 5.71%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= eqc_MortgageNotesPayableEncumbering97NewberryRoadMember		  
Outstanding indebtedness 6,819us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= eqc_MortgageNotesPayableEncumbering97NewberryRoadMember		 7,240us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= eqc_MortgageNotesPayableEncumbering97NewberryRoadMember
Secured Fixed Rate Debt    
Debt Instrument [Line Items]    
Interest rate stated percentage 5.767%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= eqc_SecuredFixedRateDebtMember		  
Outstanding indebtedness $ 598,660us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= eqc_SecuredFixedRateDebtMember		 $ 889,894us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= eqc_SecuredFixedRateDebtMember