Consolidated Statements of Equity - USD ($) $ in Thousands |
Total |
Common Stock Issued to Public Under At-the-Market Program |
Forward Equity Sale Agreement |
Preferred Shares |
Common Shares |
Common Shares
Common Stock Issued to Public Under At-the-Market Program
|
Common Shares
Forward Equity Sale Agreement
|
Additional Paid-in Capital |
Additional Paid-in Capital
Common Stock Issued to Public Under At-the-Market Program
|
Additional Paid-in Capital
Forward Equity Sale Agreement
|
Cumulative Distributions in Excess of Net Income |
Accumulated Other Comprehensive Income (Loss) |
Noncontrolling Interests |
Corporate Office Properties, L.P. |
Corporate Office Properties, L.P.
Common Stock Issued to Public Under At-the-Market Program
|
Corporate Office Properties, L.P.
Forward Equity Sale Agreement
|
Corporate Office Properties, L.P.
Common Shares
|
Corporate Office Properties, L.P.
Common Shares
Common Stock Issued to Public Under At-the-Market Program
|
Corporate Office Properties, L.P.
Common Shares
Forward Equity Sale Agreement
|
Corporate Office Properties, L.P.
Accumulated Other Comprehensive Income (Loss)
|
Corporate Office Properties, L.P.
Noncontrolling Interests
|
Corporate Office Properties, L.P.
Limited Partner
|
Corporate Office Properties, L.P.
Limited Partner
Preferred Shares
|
Corporate Office Properties, L.P.
General Partner
|
Corporate Office Properties, L.P.
General Partner
Preferred Shares
|
Balance (COPT: 98,498,651 and 101,292,299 shares as of December 31, 2016 and 2017, respectively) at Dec. 31, 2016 |
$ 1,612,777
|
|
|
$ 172,500
|
$ 985
|
|
|
$ 2,116,581
|
|
|
$ (747,825)
|
$ (1,731)
|
$ 72,267
|
$ 1,612,777
|
|
|
$ 1,419,710
|
|
|
$ (1,854)
|
$ 13,621
|
|
$ 8,800
|
|
$ 172,500
|
Balance (preferred units) at Dec. 31, 2016 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
352,000
|
|
6,900,000
|
Balance (in units/shares) at Dec. 31, 2016 |
98,498,651
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
102,089,042
|
|
|
|
|
|
|
|
|
Increase (Decrease) in Shareholders' Equity |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Redemption of preferred units resulting from redemption of preferred shares (in units) |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
(6,900,000)
|
Redemption of preferred shares (6,900,000 shares) |
$ (172,500)
|
|
|
(172,500)
|
|
|
|
6,847
|
|
|
(6,847)
|
|
|
(172,500)
|
|
|
|
|
|
|
|
|
|
|
$ (172,500)
|
Conversion of common units to common shares (COPT: 337,000 and 1,895,627 shares for the nine months ended September 30, 2017 and 2018, respectively) |
$ 0
|
|
|
|
3
|
|
|
4,599
|
|
|
|
|
(4,602)
|
|
|
|
|
|
|
|
|
|
|
|
|
Common shares issued during the period |
|
$ 19,668
|
|
|
|
$ 6
|
|
|
$ 19,662
|
|
|
|
|
|
$ 19,668
|
|
|
$ 19,668
|
|
|
|
|
|
|
|
Common shares issued during the period (in shares) |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
591,042
|
|
|
|
|
|
|
|
Issuance of common units resulting from exercise of share options (in units) |
5,000
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
5,000
|
|
|
|
|
|
|
|
|
Issuance of common units resulting from exercise of share options (COPT: 5,000 shares for the nine months ended September 30, 2017) |
$ 150
|
|
|
|
0
|
|
|
150
|
|
|
|
|
|
150
|
|
|
$ 150
|
|
|
|
|
|
|
|
|
Share-based compensation issuance, net of redemptions (in units/shares) |
176,477
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
176,477
|
|
|
|
|
|
|
|
|
Share-based compensation issuance, net of redemptions (COPT: 176,477 and 141,633 shares issued, net of redemptions for the nine months ended September 30, 2017 and 2018, respectively) |
$ 4,444
|
|
|
|
2
|
|
|
4,442
|
|
|
|
|
|
4,444
|
|
|
$ 4,444
|
|
|
|
|
|
|
|
|
Redemption of vested equity awards |
(1,869)
|
|
|
|
|
|
|
(1,869)
|
|
|
|
|
|
(1,869)
|
|
|
(1,869)
|
|
|
|
|
|
|
|
|
Adjustments to noncontrolling interests resulting from changes in ownership of COPLP |
0
|
|
|
|
|
|
|
(589)
|
|
|
|
|
589
|
|
|
|
|
|
|
|
|
|
|
|
|
Comprehensive income |
63,115
|
|
|
|
|
|
|
|
|
|
59,124
|
872
|
3,119
|
63,115
|
|
|
54,481
|
|
|
902
|
1,018
|
|
$ 495
|
|
6,219
|
Dividends / Distributions to owners of common and preferred units |
(88,300)
|
|
|
|
|
|
|
|
|
|
(88,300)
|
|
|
(91,562)
|
|
|
(84,848)
|
|
|
|
|
|
$ (495)
|
|
$ (6,219)
|
Distributions to owners of common and preferred units in COPLP |
(3,262)
|
|
|
|
|
|
|
|
|
|
|
|
(3,262)
|
|
|
|
|
|
|
|
|
|
|
|
|
Distributions to noncontrolling interests in subsidiaries |
(2,614)
|
|
|
|
|
|
|
|
|
|
|
|
(2,614)
|
(2,614)
|
|
|
|
|
|
|
(2,614)
|
|
|
|
|
Adjustment to arrive at fair value of redeemable noncontrolling interests |
$ 244
|
|
|
|
|
|
|
244
|
|
|
|
|
|
244
|
|
|
$ 244
|
|
|
|
|
|
|
|
|
Balance (in units/shares) at Sep. 30, 2017 |
99,608,170
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
102,861,561
|
|
|
|
|
|
|
|
|
Balance (preferred units) at Sep. 30, 2017 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
352,000
|
|
0
|
Balance (COPT: 99,608,170 shares and 108,848,223 shares as of September 30, 2017 and 2018, respectively) at Sep. 30, 2017 |
$ 1,431,853
|
|
|
0
|
996
|
|
|
2,150,067
|
|
|
(783,848)
|
(859)
|
65,497
|
1,431,853
|
|
|
$ 1,411,980
|
|
|
(952)
|
12,025
|
|
$ 8,800
|
|
$ 0
|
Increase (Decrease) in Shareholders' Equity |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Cumulative effect of accounting change for adoption of hedge accounting guidance |
|
|
|
|
|
|
|
|
|
|
(276)
|
276
|
|
|
|
|
(276)
|
|
|
276
|
|
|
|
|
|
Balance, as adjusted |
1,468,307
|
|
|
0
|
1,013
|
|
|
2,201,047
|
|
|
(802,361)
|
2,443
|
66,165
|
1,468,307
|
|
|
1,444,746
|
|
|
2,449
|
12,312
|
|
8,800
|
|
0
|
Balance (COPT: 98,498,651 and 101,292,299 shares as of December 31, 2016 and 2017, respectively) at Dec. 31, 2017 |
$ 1,468,307
|
|
|
0
|
1,013
|
|
|
2,201,047
|
|
|
(802,085)
|
2,167
|
66,165
|
1,468,307
|
|
|
$ 1,445,022
|
|
|
2,173
|
12,312
|
|
$ 8,800
|
|
$ 0
|
Balance (preferred units) at Dec. 31, 2017 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
352,000
|
352,000
|
|
0
|
Balance (in units/shares) at Dec. 31, 2017 |
101,292,299
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
104,543,177
|
|
|
|
|
3,250,878
|
|
101,292,299
|
|
Increase (Decrease) in Shareholders' Equity |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Conversion of common units to common shares (COPT: 337,000 and 1,895,627 shares for the nine months ended September 30, 2017 and 2018, respectively) |
$ 0
|
|
|
|
19
|
|
|
27,263
|
|
|
|
|
(27,282)
|
|
|
|
|
|
|
|
|
|
|
|
|
Common shares issued during the period |
|
$ 29,732
|
$ 132,330
|
|
|
$ 10
|
$ 45
|
|
$ 29,722
|
$ 132,285
|
|
|
|
|
$ 29,732
|
$ 132,330
|
|
$ 29,732
|
$ 132,330
|
|
|
|
|
|
|
Common shares issued during the period (in shares) |
|
|
4,527,000
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
991,664
|
4,527,000
|
|
|
|
|
|
|
Share-based compensation issuance, net of redemptions (in units/shares) |
141,633
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
141,633
|
|
|
|
|
|
|
|
|
Share-based compensation issuance, net of redemptions (COPT: 176,477 and 141,633 shares issued, net of redemptions for the nine months ended September 30, 2017 and 2018, respectively) |
$ 5,179
|
|
|
|
1
|
|
|
5,178
|
|
|
|
|
|
5,179
|
|
|
$ 5,179
|
|
|
|
|
|
|
|
|
Redemption of vested equity awards |
(1,611)
|
|
|
|
|
|
|
(1,611)
|
|
|
|
|
|
(1,611)
|
|
|
(1,611)
|
|
|
|
|
|
|
|
|
Adjustments to noncontrolling interests resulting from changes in ownership of COPLP |
0
|
|
|
|
|
|
|
(2,069)
|
|
|
|
|
2,069
|
|
|
|
|
|
|
|
|
|
|
|
|
Comprehensive income |
66,188
|
|
|
|
|
|
|
|
|
|
55,281
|
7,665
|
3,242
|
66,188
|
|
|
56,813
|
|
|
7,904
|
976
|
|
$ 495
|
|
$ 0
|
Dividends / Distributions to owners of common and preferred units |
(86,428)
|
|
|
|
|
|
|
|
|
|
(86,428)
|
|
|
(89,054)
|
|
|
(88,559)
|
|
|
|
|
|
$ (495)
|
|
$ 0
|
Distributions to owners of common and preferred units in COPLP |
(2,626)
|
|
|
|
|
|
|
|
|
|
|
|
(2,626)
|
|
|
|
|
|
|
|
|
|
|
|
|
Distributions to noncontrolling interests in subsidiaries |
(11)
|
|
|
|
|
|
|
|
|
|
|
|
(11)
|
(11)
|
|
|
|
|
|
|
(11)
|
|
|
|
|
Adjustment to arrive at fair value of redeemable noncontrolling interests |
$ (1,331)
|
|
|
|
|
|
|
(1,331)
|
|
|
|
|
|
(1,331)
|
|
|
$ (1,331)
|
|
|
|
|
|
|
|
|
Balance (in units/shares) at Sep. 30, 2018 |
108,848,223
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
110,203,474
|
|
|
|
|
1,355,251
|
|
108,848,223
|
|
Balance (preferred units) at Sep. 30, 2018 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
352,000
|
352,000
|
|
0
|
Balance (COPT: 99,608,170 shares and 108,848,223 shares as of September 30, 2017 and 2018, respectively) at Sep. 30, 2018 |
$ 1,609,729
|
|
|
$ 0
|
$ 1,088
|
|
|
$ 2,390,484
|
|
|
$ (833,508)
|
$ 10,108
|
$ 41,557
|
$ 1,609,729
|
|
|
$ 1,577,299
|
|
|
$ 10,353
|
$ 13,277
|
|
$ 8,800
|
|
$ 0
|