Acquisitions (Details) (USD $) In Millions, unless otherwise specified		6 Months Ended		5 Months Ended		3 Months Ended		0 Months Ended		6 Months Ended
	Sep. 30, 2011 Unsecured Debt [Member] Unsecured $500 Million Facility [Member]	Sep. 30, 2011 1200 Enclave Parkway Building [Member] squarefeet	Mar. 30, 2011 1200 Enclave Parkway Building [Member]	Sep. 30, 2011 The Dupree Building [Member] squarefeet	Apr. 29, 2011 The Dupree Building [Member]	Sep. 30, 2011 The Medici Building [Member] squarefeet	Jun. 07, 2011 The Medici Building [Member]	Sep. 30, 2011 The 225 and 235 Presidential Way Buildings squarefeet	Sep. 13, 2011 The 225 and 235 Presidential Way Buildings	Sep. 30, 2011 500 W. Monroe Building [Member] squarefeet	Mar. 31, 2011 500 W. Monroe Building [Member]
Business Acquisition [Line Items]
Debt Instrument, Face Amount	$ 500.0
Number of Buildings			1		1		1		2		1
Rentable Square Feet		149,654		137,818		152,221		440,130		962,361
Percentage Occupied as of Acquisition Date			18.00%		83.00%		22.00%		100.00%		67.00%
Acquisition Price			$ 18.5		$ 20.5		$ 13.2		$ 85.3		$ 227.5	[1]

[1] Represents the estimated fair value of real estate assets acquired as recorded in Piedmont’s accompanying consolidated balance sheet as of the acquisition date.