COPT Defense Properties Annual report pursuant to Section 13 and 15(d)

Annual report pursuant to Section 13 and 15(d)

Intangible Assets on Real Estate Acquisitions (Details)

Intangible Assets on Real Estate Acquisitions (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Intangible assets on real estate acquisitions
Gross Carrying Amount	$ 188,467,000	$ 192,592,000
Accumulated Amortization	144,613,000	133,334,000
Net Carrying Amount	43,854,000	59,258,000
Amortization of the intangible assets	15,200,000us-gaap_AmortizationOfIntangibleAssets	16,200,000us-gaap_AmortizationOfIntangibleAssets	21,400,000us-gaap_AmortizationOfIntangibleAssets
Weighted average amortization period of intangible assets	10 years
Estimated future amortization expense associated with the intangible asset categories for the next five years
2015	9,300,000
2016	8,400,000
2017	6,200,000
2018	3,800,000
2019	3,400,000
In-place lease value
Intangible assets on real estate acquisitions
Gross Carrying Amount	123,759,000	125,504,000
Accumulated Amortization	101,040,000	93,885,000
Net Carrying Amount	22,719,000	31,619,000
Weighted average amortization period of intangible assets	6 years
Tenant relationship value
Intangible assets on real estate acquisitions
Gross Carrying Amount	42,301,000	44,414,000
Accumulated Amortization	28,492,000	25,962,000
Net Carrying Amount	13,809,000	18,452,000
Weighted average amortization period of intangible assets	7 years
Below-market cost arrangements
Intangible assets on real estate acquisitions
Gross Carrying Amount	12,415,000	12,416,000
Accumulated Amortization	5,984,000	5,136,000
Net Carrying Amount	6,431,000	7,280,000
Weighted average amortization period of intangible assets	31 years
Above-market leases
Intangible assets on real estate acquisitions
Gross Carrying Amount	8,659,000	8,925,000
Accumulated Amortization	8,159,000	7,970,000
Net Carrying Amount	500,000	955,000
Weighted average amortization period of intangible assets	2 years
Market concentration premium
Intangible assets on real estate acquisitions
Gross Carrying Amount	1,333,000	1,333,000
Accumulated Amortization	938,000	381,000
Net Carrying Amount	$ 395,000	$ 952,000
Weighted average amortization period of intangible assets	28 years