Discontinued Operations (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended			0 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Jul. 02, 2011 Eastpointe Corporate Center [Member]	Aug. 31, 2011 Corporate Court 5000 [Member]	Dec. 15, 2011 W Wacker Building 35 [Member]		Mar. 19, 2012 Portland Portfolio [Member] property acre		May 31, 2012 26200 Enterprise Way [Member]	Sep. 21, 2012 Hidden Lake Circle Buildings [Member]	Mar. 28, 2013 1111 Durham Avenue [Member]	May 01, 2013 Enclave 1200 Parkway [Member]	Nov. 01, 2013 350 Spectrum Loop [Member]	Dec. 30, 2013 8700 South Price Road [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on sale of real estate assets									$ 31,292	$ 27,577	$ 122,657	$ 12,152	$ 14,367	$ 96,138	[1]	$ 17,823	[2]	$ 10,013	$ (259)	$ (9)	$ 16,246	$ 7,959	$ 7,096
Net Sales Proceeds									95,671	93,839	291,785	31,704	36,100	223,981	[1]	43,832	[2]	24,412	25,595	3,752	45,552	29,676	16,691
Percent of ownership interest In real estate property disposal														96.50%
Number of real estate properties sold																4
Acreage																18.19
Revenues:
Rental income									4,678	13,215	45,306
Tenant reimbursements									757	1,528	20,632
Revenue									5,435	14,743	65,938
Expenses:
Property operating costs									1,900	5,216	26,243
Depreciation									1,004	3,291	9,044
Amortization									209	690	5,995
General and administrative									2	45	(168)
Expenses									3,115	9,242	41,114
Other income (expense):
Interest expense									0	0	(5,931)
Interest income and other income/(expense)									26	0	(91)
Net casualty recoveries									17	0	0
Net loss attributable to noncontrolling interest									0	0	(453)
Other income (expense)									43	0	(6,475)
Operating income, excluding impairment loss and gain on sale of real estate assets									2,363	5,501	18,349
Impairment loss									(6,402)	0	0
Income from discontinued operations	$ 15,468	$ 412	$ 17,083	$ (5,710)	$ 1,809	$ 612	$ 11,133	$ 19,524	$ 27,253	$ 33,078	$ 141,006

[1] Piedmont sold its approximate 96.5% ownership in the property. Transaction data above is presented at Piedmont's ownership percentage.

[2] The Portland Portfolio consisted of four office properties known as the Deschutes building, the Rhein building, the Rogue building, and the Willamette building, as well as 18.19 acres of adjoining, undeveloped land.