Derivative Instruments (Details) (USD $)	3 Months Ended		9 Months Ended					3 Months Ended		9 Months Ended		3 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010	Dec. 31, 2010	Jun. 27, 2011 Unsecured Debt [Member] Unsecured $250 Million Term Loan [Member]	Sep. 30, 2011 Secured Debt [Member] 500 W. Monroe Mezzanine I Loan- A Participation $45 Million [Member]	Sep. 30, 2011 Interest Rate Contract [Member]	Sep. 30, 2010 Interest Rate Contract [Member]	Sep. 30, 2011 Interest Rate Contract [Member]	Sep. 30, 2010 Interest Rate Contract [Member]	Sep. 30, 2011 Interest Rate Cap [Member]	Sep. 30, 2011 Interest Rate Cap 1 [Member]		Sep. 30, 2011 Interest Rate Cap 2 [Member]
Derivative [Line Items]
Debt Instrument, Face Amount						$ 250,000,000	$ 45,000,000
Notional Amount												202,000,000	140,000,000	[1]	62,000,000	[1],[2]
Amount of loss recognized in OCI on derivative								0	637,000	204,000	1,483,000
Amount of previously recorded loss reclassified from accumulated OCI into interest expense								(44,000)	(350,000)	(895,000)	(4,321,000)
Gain (Loss) on Interest Rate Cash Flow Hedge Ineffectiveness	0	0	0	0
Interest rate swap					691,000
Interest Rate Fair Value Hedge Derivative at Fair Value, Net												3,000
Number of Interest Rate Derivatives Held												2
Increase (Decrease) in Fair Value of Interest Rate Fair Value Hedging Instruments												$ 44,000

[1] Mirrors the monthly interest accrual period of the 500 W. Monroe Loans.

[2] Interest rate cap agreement is inclusive of both the $45.0 Million 500 W. Monroe Mezzanine I Loan- A Participation payable to an unrelated third-party, as well as the loan participation formerly owned by Piedmont as a note receivable.