Variable Interest Entities (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2016	Dec. 31, 2015
Eye Street 1201 N.W. Associates LLC [Member]
Variable Interest Entity [Line Items]
Piedmont’s % Ownership of Entity		49.50%
Net Carrying Amount		$ (7.5)	$ (7.4)
Variable interest entity, cash flow percent entitled to entity		100.00%
Eye Street 1225 N.W. Associates LLC [Member]
Variable Interest Entity [Line Items]
Piedmont’s % Ownership of Entity		49.50%
Net Carrying Amount		$ 6.7	3.8
Variable interest entity, cash flow percent entitled to entity		100.00%
Piedmont 500 W. Monroe Fee LLC [Member]
Variable Interest Entity [Line Items]
Piedmont’s % Ownership of Entity		100.00%
Net Carrying Amount		$ 253.2	$ 251.4
Variable interest entity, cash flow percent entitled to entity			100.00%
Piedmont TownPark Land, LLC [Member]
Variable Interest Entity [Line Items]
Piedmont’s % Ownership of Entity	[1]	100.00%
Net Carrying Amount	[1]	$ 6.0	$ 6.0

[1] As of April 25, 2016, Piedmont terminated the equity participation rights agreement related to Piedmont TownPark Land, LLC., without any pay out required.