Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Cumulative Distributions in Excess of Earnings [Member]	Other Comprehensive Loss [Member]	Non-controlling Interest [Member]
Balance at Dec. 31, 2013	$ 2,461,159	$ 1,575	$ 3,668,906	$ (1,231,209)	$ 20,278	$ 1,609
Balance (in shares) at Dec. 31, 2013		157,461,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share repurchases as part of an announced plan	(52,796)	$ (32)		(52,764)
Share repurchases as part of an announced plan, shares		(3,190,000)
Retirement of shares returned from escrow	(1,479)	$ (1)	(1,478)
Retirement of shares returned from escrow, shares		(85,000)
Redemption of noncontrolling interest in consolidated variable interest entity	(4,054)		(4,054)
Dividends to common stockholders ($0.81 (YTD 2014) and $0.42 (YTD 2015) per share), distributions to noncontrolling interest, and dividends reinvested	(125,198)		(188)	(124,995)		(15)
Shares issued and amortized under the 2007 Omnibus Incentive Plan, net of tax	2,997	$ 1	2,996
Shares issued and amortized under the 2007 Omnibus Incentive Plan, net of tax (in shares)		138,000
Net income attributable to noncontrolling interest	15					15
Net income attributable to Piedmont	43,348			43,348
Other comprehensive income (loss)	(11,977)				(11,977)
Balance at Dec. 31, 2014	$ 2,312,015	$ 1,543	3,666,182	(1,365,620)	8,301	1,609
Balance (in shares) at Dec. 31, 2014	154,324,089	154,324,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share repurchases as part of an announced plan	$ (46,259)	$ (26)		(46,233)
Share repurchases as part of an announced plan, shares		(2,649,000)
Offering costs	(326)		(326)
Redemption of noncontrolling interest in consolidated variable interest entity	54		54
Reallocation of noncontrolling interest of subsidiary	544		1,128			(584)
Dividends to common stockholders ($0.81 (YTD 2014) and $0.42 (YTD 2015) per share), distributions to noncontrolling interest, and dividends reinvested	(64,828)		(140)	(64,680)		(8)
Shares issued and amortized under the 2007 Omnibus Incentive Plan, net of tax	1,481	$ 1	1,480
Shares issued and amortized under the 2007 Omnibus Incentive Plan, net of tax (in shares)		158,000
Net income attributable to noncontrolling interest	8					8
Net income attributable to Piedmont	49,221			49,221
Other comprehensive income (loss)	3,941				3,941
Balance at Jun. 30, 2015	$ 2,255,851	$ 1,518	$ 3,668,378	$ (1,427,312)	$ 12,242	$ 1,025
Balance (in shares) at Jun. 30, 2015	151,833,222	151,833,000