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 |