Capital and Financing Transactions - Mortgage Notes Payable (Details) - USD ($) $ in Thousands					3 Months Ended		6 Months Ended
	Apr. 08, 2015	Apr. 06, 2015	Apr. 03, 2015	Mar. 05, 2015	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Debt Instrument [Line Items]
Loss on extinguishment of debt					$ (4,919)	$ 0	$ (4,840)	$ 0
Repayments of secured debt							145,989	$ 39,396
Long-term construction loan					11,300		11,300
Mortgages
Debt Instrument [Line Items]
Modified mortgage loan					1,200,000		1,200,000
Unamortized premium on debt acquired					$ 21,900		$ 21,900
Effective interest rate on notes payable					4.20%		4.20%
Westshore Corporate Center | Mortgages
Debt Instrument [Line Items]
Amount of debt extinguishment				$ 14,000
Loss on extinguishment of debt				$ 79
Hillsboro I-V, Peachtree Dunwoody, One Commerce Green and Comerica Bank Building | Mortgages
Debt Instrument [Line Items]
Repayments of secured debt			$ 68,000
Payments of debt extinguishment costs			$ 3,000
3350 Peachtree | Mortgages
Debt Instrument [Line Items]
Repayments of secured debt		$ 31,900
Payments of debt extinguishment costs		$ 319
Parkway Properties Office Fund II, LP | Mortgages
Debt Instrument [Line Items]
Repayments of secured debt	$ 22,100
Payments of debt extinguishment costs	1,800
Parkway Properties Office Fund II, LP | Hayden Ferry Lakeside III
Debt Instrument [Line Items]
Proceeds from construction loan							$ 10,800
Parent Company | Mortgages
Debt Instrument [Line Items]
Payments of debt extinguishment costs	$ 525