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Fair Value Measurements (Details 2) - USD ($) $ in Thousands | Dec. 31, 2016 | Dec. 31, 2015
--- | --- | ---
Liabilities: |  |
Interest rate derivatives | $ 1,572 | $ 3,160
Fair value measurement on a recurring basis [Member] |  |
Assets: |  |
Interest rate derivatives | 158 | 53
Assets | 5,595 | 5,816
Liabilities: |  |
Deferred compensation plan liability | 5,437 | 5,763
Interest rate derivatives | 1,572 | 3,160
Redeemable preferred shares of beneficial interest | 26,583 |
Liabilities | 33,592 | 8,923
Fair value measurement on a recurring basis [Member] | Mutual funds [Member] |  |
Assets: |  |
Marketable securities in deferred compensation plan | 5,346 | 5,658
Fair value measurement on a recurring basis [Member] | Other [Member] |  |
Assets: |  |
Marketable securities in deferred compensation plan | 91 | 105
Fair value measurement on a recurring basis [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] |  |
Assets: |  |
Assets | 5,437 | 5,763
Liabilities: |  |
Liabilities | 0 | 0
Fair value measurement on a recurring basis [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Mutual funds [Member] |  |
Assets: |  |
Marketable securities in deferred compensation plan | 5,346 | 5,658
Fair value measurement on a recurring basis [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Other [Member] |  |
Assets: |  |
Marketable securities in deferred compensation plan | 91 | 105
Fair value measurement on a recurring basis [Member] | Significant Other Observable Inputs (Level 2) [Member] |  |
Assets: |  |
Interest rate derivatives | 158 | 53
Assets | 158 | 53
Liabilities: |  |
Deferred compensation plan liability | 5,437 | 5,763
Interest rate derivatives | 1,572 | 3,160
Redeemable preferred shares of beneficial interest | 26,583 |
Liabilities | 33,592 | 8,923
Corporate Office Properties, L.P. [Member] |  |
Liabilities: |  |
Interest rate derivatives | 1,572 | 3,160
Corporate Office Properties, L.P. [Member] | Fair value measurement on a recurring basis [Member] |  |
Assets: |  |
Interest rate derivatives | 158 | 53
Liabilities: |  |
Interest rate derivatives | 1,572 | 3,160
Redeemable preferred shares of beneficial interest | 26,583 |
Liabilities | 28,155 |
Corporate Office Properties, L.P. [Member] | Fair value measurement on a recurring basis [Member] | Significant Other Observable Inputs (Level 2) [Member] |  |
Assets: |  |
Interest rate derivatives | 158 | 53
Liabilities: |  |
Interest rate derivatives | 1,572 | $ 3,160
Redeemable preferred shares of beneficial interest | 26,583 |
Liabilities | $ 28,155 |

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