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Subsequent Events (Details) (USD $)
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0 Months Ended | 6 Months Ended | 0 Months Ended | 6 Months Ended | 0 Months Ended | 6 Months Ended | 0 Months Ended | 6 Months Ended | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
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Mar. 19, 2013
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Jun. 30, 2013
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Jun. 30, 2012
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Dec. 31, 2012
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Mar. 19, 2013
Corporate Office Properties, L.P.
|
Jun. 30, 2013
Corporate Office Properties, L.P.
|
Jun. 30, 2012
Corporate Office Properties, L.P.
|
Jul. 12, 2013
Corporate Office Properties, L.P.
Subsequent Event
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Jul. 16, 2013
Amendment to Revolving Credit Facility
Revolving Credit Facility
Subsequent Event
|
Jul. 16, 2013
Amendment to Revolving Credit Facility
London Interbank Offered Rate (LIBOR)
Revolving Credit Facility
Subsequent Event
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Jun. 30, 2013
Amendment to Revolving Credit Facility
London Interbank Offered Rate (LIBOR)
Revolving Credit Facility
Subsequent Event
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Jun. 30, 2013
Common Shares
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Jul. 12, 2013
Common Shares
Subsequent Event
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Jun. 30, 2013
Common Shares
Corporate Office Properties, L.P.
|
Jun. 30, 2012
Common Shares
Corporate Office Properties, L.P.
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Jun. 30, 2013
Term Loan Facility
Amendment to Term Loan Facilities
Unsecured Debt
Subsequent Event
|
Jul. 16, 2013
Term Loan Facility
Amendment to Term Loan Facilities
London Interbank Offered Rate (LIBOR)
Subsequent Event
|
Jun. 30, 2013
Term Loan Facility
Amendment to Term Loan Facilities
London Interbank Offered Rate (LIBOR)
Subsequent Event
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| Subsequent Event [Line Items] | ||||||||||||||||||
| Shares issued to the public (in shares) | 4,485,000 | 4,485,000 | 1,500,000.0 | 4,485,000 | ||||||||||||||
| Issuance of stock, weighted average price per share | $ 26.05 | |||||||||||||||||
| Shares issued to the public (in dollars) | $ 118,100,000 | $ 117,913,000 | $ 165,665,000 | $ 117,913,000 | $ 165,665,000 | $ 45,000 | $ 38,500,000 | $ 117,913,000 | $ (6,835,000) | |||||||||
| Payments of Stock Issuance Costs | 586,000 | |||||||||||||||||
| Common Stock, Shares, Issued | 85,845,403 | 80,952,986 | 1,500,000.0 | |||||||||||||||
| Debt instrument, extension option, term | 1 year | |||||||||||||||||
| Line of credit facility, extension fee percentage | 0.15% | |||||||||||||||||
| Variable rate, spread (as a percent) | 1.75% | 0.975% | 1.10% | 2.00% | ||||||||||||||
| Debt instrument, face amount | $ 550,000,000 | |||||||||||||||||