Annual report pursuant to Section 13 and 15(d)

Quarterly Data (Unaudited) (Details)

v2.4.0.6
Quarterly Data (Unaudited) (Details) (USD $)
In Thousands, except Per Share data, unless otherwise specified
3 Months Ended 12 Months Ended
Dec. 31, 2012
Sep. 30, 2012
Jun. 30, 2012
Mar. 31, 2012
Dec. 31, 2011
Sep. 30, 2011
Jun. 30, 2011
Mar. 31, 2011
Dec. 31, 2012
Dec. 31, 2011
Dec. 31, 2010
Quarterly Financial Information Disclosure [Abstract]                      
Revenues $ 137,505 $ 130,144 $ 128,163 $ 132,195 $ 127,974 $ 126,707 $ 131,840 $ 126,320 $ 528,007 $ 512,841 $ 492,234
Operating income (loss) 34,522 (8,586) 33,837 36,192 (9,007) 27,400 16,600 787 95,965 35,780 110,514
Income (loss) from continuing operations 15,743 (31,850) 10,065 12,685 (60,325) 1,669 (397) (22,851) 6,643 (81,904) 25,621
Discontinued operations 3,267 11,085 1,775 (2,450) (30,781) 5,801 (25,008) 1,584 13,677 (48,404) 17,054
Net income (loss) 19,010 (20,765) 11,861 10,235 (91,102) 7,470 (25,378) (18,566) 20,341 (127,576) 45,504
Net income (loss) attributable to noncontrolling interests (471) 1,603 (556) 60 5,606 (626) 1,964 1,204      
Net income (loss) attributable to Corporate Office Properties Trust 18,539 (19,162) 11,305 10,295 (85,496) 6,844 (23,414) (17,362) 20,977 (119,428) 42,760
Preferred share dividends (6,106) (6,546) (4,167) (4,025) (4,026) (4,025) (4,026) (4,025) (20,844) (16,102) (16,102)
Net loss attributable to Corporate Office Properties Trust common shareholders $ 12,433 $ (27,535) $ 7,138 $ 6,270 $ (89,522) $ 2,819 $ (27,440) $ (21,387) $ (1,694) $ (135,530) $ 26,658
Basic earnings per share:                      
Income (loss) from continuing operations (in dollars per share)                 $ (0.21) [1] $ (1.31) [1] $ 0.17 [1]
Net (loss) income attributable to COPT common shareholders (in dollars per share) $ 0.16 $ (0.39) $ 0.10 $ 0.09 $ (1.26) $ 0.04 $ (0.40) $ (0.33) $ (0.03) [1] $ (1.97) [1] $ 0.43 [1]
Diluted earnings per share:                      
(Loss) income from continuing operations (in dollars per share)                 $ (0.21) [1] $ (1.31) [1] $ 0.17 [1]
Earnings per share, diluted $ 0.16 $ (0.39) $ 0.10 $ 0.09 $ (1.26) $ 0.04 $ (0.41) $ (0.33) $ (0.03) [1] $ (1.97) [1] $ 0.43 [1]
[1] Basic and diluted earnings per common share are calculated based on amounts attributable to common shareholders of Corporate Office Properties Trust.