Property Dispositions, Assets Held for Sale and Discontinued Operations (Property Dispositions) (Details) $ in Thousands													12 Months Ended
		Dec. 21, 2015 USD ($)	Oct. 29, 2015 USD ($)	Sep. 01, 2015 USD ($)	Aug. 10, 2015 USD ($)	Jul. 28, 2015 USD ($)	May. 01, 2015 USD ($) term	Apr. 29, 2015 USD ($)	Apr. 28, 2015 USD ($)	Jan. 30, 2015 USD ($)	May. 29, 2014 USD ($)	May. 19, 2014 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net Sales Proceeds													$ 848,169	$ 46,232	$ 95,671
Notes receivable													$ 45,400	$ 0
Copper Ridge Center [Member] | Notes Receivable [Member] | Secured Promissory Note [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Interest rate percentage for unsecured promissory note							8.45%
Notes receivable							$ 45,400
Number of terms in which unsecured promissory note may be extended | term							2
Duration of extension period							6 months
Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member] | 2020 W. 89th STREET [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain/(Loss) on Sale												$ 1,132
Net Sales Proceeds												$ 5,515
Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member] | Two Park Center [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain/(Loss) on Sale	[1]										$ (169)
Net Sales Proceeds	[1]										$ 6,017
Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member] | 3900 Dallas Parkway [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain/(Loss) on Sale										$ 10,073
Net Sales Proceeds										$ 25,803
Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member] | 5601 Headquarters Drive [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain/(Loss) on Sale									$ 7,959
Net Sales Proceeds									$ 33,326
Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member] | River Corporate Center [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain/(Loss) on Sale								$ 5,297
Net Sales Proceeds								$ 24,223
Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member] | Copper Ridge Center [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain/(Loss) on Sale	[2]						$ 13,731
Net Sales Proceeds	[2]						$ 4,972
Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member] | Eastpoint I & II [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain/(Loss) on Sale						$ (177)
Net Sales Proceeds						$ 17,342
Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member] | 3750 Brookside Parkway [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain/(Loss) on Sale					$ 1,406
Net Sales Proceeds					$ 13,624
Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member] | Chandler Forum [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain/(Loss) on Sale				$ 15,506
Net Sales Proceeds				$ 32,267
Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member] | Aon Center [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain/(Loss) on Sale			$ 114,264
Net Sales Proceeds			$ 646,243
Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member] | 2 Gatehall Drive [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain/(Loss) on Sale		$ 178
Net Sales Proceeds		$ 50,369

[1] Property was owned as part of the unconsolidated joint venture, Fund XIII and REIT Joint Venture. As such, the loss on sale was presented as equity in income/(loss) of unconsolidated joint ventures.

[2] As part of the transaction, Piedmont accepted a 8.45% interest bearing, secured promissory note from the buyer for the remaining $45.4 million owed on the sale. During the year ended December 31, 2015, the purchaser exercised the first of two, six month extension options, extending the maturity date of the note receivable to June 30, 2016.