Subsequent Events (Details) (USD $)	0 Months Ended	3 Months Ended		9 Months Ended					0 Months Ended			0 Months Ended		0 Months Ended			0 Months Ended
	Sep. 16, 2014	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014 Valleybrooke Office Park [Member]	Oct. 24, 2014 Valleybrooke Office Park [Member]	Oct. 21, 2014 1919 Venture [Member]	Oct. 17, 2014 River Place [Member]	Oct. 17, 2014 River Place [Member] sqft Real_Estate_Investments	Oct. 21, 2014 Brandywine Realty Trust [Member] 1919 Venture [Member]	Oct. 17, 2014 Brandywine Realty Trust [Member] River Place [Member]	Oct. 21, 2014 LCOR/Calstrs [Member] 1919 Venture [Member]	Oct. 17, 2014 DRA Advisors LLC [Member] River Place [Member]	Oct. 16, 2014 2014 5.400% Notes Debt Instrument, Redemption [Member]	Oct. 16, 2014 2015 7.500% Notes Debt Instrument, Redemption [Member]	Oct. 16, 2014 Note Four and Five [Member] Debt Instrument, Redemption [Member]
Subsequent Event [Line Items]
Sale Consideration Of Sold Property							$ 37,900,000
Provision for impairment on assets held for sale		1,765,000	0	1,765,000	0	1,765,000
Equity Method Investment, Ownership Percentage								50.00%
Amount Of Participant Contribution													8,200,000
General Partners' Contributed Capital											5,200,000
Aggregate gross sales price of a joint venture								16,400,000
Equity Method Investment, Short-term Loan									88,000,000
Number of Real Estate Properties										7
Net Rentable Space										591,000
Equity method investment, Consideration transferred									128,100,000
Equity method investments, Cash contributions												20,000,000		20,000,000
Short-term Debt, Terms									4.0% through December 31, 2014 (ii) 5.0% from January 1, 2015 through January 31, 2015, (iii) 7.0% from February 1, 2015 through February 28, 2015 and (iv) 9.0% from March 1, 2015 through March 31, 2015.
Long-term Debt, Gross															143,500,000	114,900,000
Debt Instrument, Interest Rate, Stated Percentage															5.40%	7.50%
Repayments of Notes Payable																	270,300,000
Loss on early extinguishment of debt	$ 2,606,000	$ (2,606,000)	$ (11,000)	$ (2,606,000)	$ (1,127,000)												$ 4,900,000