Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common  Stock	Additional Paid-In Capital	Cumulative Distributions in Excess of Earnings	Other Comprehensive Income/(Loss)	Non- controlling Interest
Beginning balance (in shares) at Dec. 31, 2018		126,219,000
Balance at Dec. 31, 2018	$ 1,712,140	$ 1,262	$ 3,683,186	$ (1,982,542)	$ 8,462	$ 1,772
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Offering costs	(700)		(700)
Share repurchases as part of announced plan (in shares)		(728,000)
Share repurchases as part of an announced plan	(12,482)	$ (7)		(12,475)
Dividends to common stockholders, stockholders of subsidiaries, and dividends reinvested	(79,447)		(216)	(79,204)		(27)
Shares issued and amortized under the 2007 Omnibus Incentive Plan, net of tax (in shares)		292,000
Shares issued and amortized under the 2007 Omnibus Incentive Plan, net of tax	3,237	$ 3	3,234
Net loss applicable to noncontrolling interest	(3)					(3)
Net income applicable to Piedmont	66,783			66,783
Other comprehensive loss	(8,745)				(8,745)
Ending balance (in shares) at Sep. 30, 2019		125,783,000
Balance at Sep. 30, 2019	1,680,783	$ 1,258	3,685,504	(2,007,438)	(283)	1,742
Beginning balance (in shares) at Jun. 30, 2019		125,783,000
Balance at Jun. 30, 2019	1,702,975	$ 1,258	3,687,881	(1,989,446)	1,530	1,752
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Offering costs	(700)		(700)
Dividends to common stockholders, stockholders of subsidiaries, and dividends reinvested	(26,495)		(74)	(26,414)		(7)
Shares issued and amortized under the 2007 Omnibus Incentive Plan, net of tax (in shares)		0
Shares issued and amortized under the 2007 Omnibus Incentive Plan, net of tax	(1,603)	$ 0	(1,603)
Net loss applicable to noncontrolling interest	(3)					(3)
Net income applicable to Piedmont	8,422			8,422
Other comprehensive loss	(1,813)				(1,813)
Ending balance (in shares) at Sep. 30, 2019		125,783,000
Balance at Sep. 30, 2019	$ 1,680,783	$ 1,258	3,685,504	(2,007,438)	(283)	1,742
Beginning balance (in shares) at Dec. 31, 2019	125,783,408	125,783,000
Balance at Dec. 31, 2019	$ 1,818,974	$ 1,258	3,686,398	(1,871,375)	967	1,726
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends to common stockholders, stockholders of subsidiaries, and dividends reinvested	(79,405)		(5)	(79,374)		(26)
Shares issued and amortized under the 2007 Omnibus Incentive Plan, net of tax (in shares)		246,000
Shares issued and amortized under the 2007 Omnibus Incentive Plan, net of tax	6,243	$ 2	6,241
Net loss applicable to noncontrolling interest	(2)					(2)
Net income applicable to Piedmont	210,079			210,079
Other comprehensive loss	$ (25,960)				(25,960)
Ending balance (in shares) at Sep. 30, 2020	126,028,762	126,029,000
Balance at Sep. 30, 2020	$ 1,929,929	$ 1,260	3,692,634	(1,740,670)	(24,993)	1,698
Beginning balance (in shares) at Jun. 30, 2020		126,025,000
Balance at Jun. 30, 2020	1,947,837	$ 1,260	3,691,377	(1,723,147)	(23,360)	1,707
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends to common stockholders, stockholders of subsidiaries, and dividends reinvested	(26,472)			(26,466)		(6)
Shares issued and amortized under the 2007 Omnibus Incentive Plan, net of tax (in shares)		4,000
Shares issued and amortized under the 2007 Omnibus Incentive Plan, net of tax	1,257	$ 0	1,257
Net loss applicable to noncontrolling interest	(3)					(3)
Net income applicable to Piedmont	8,943			8,943
Other comprehensive loss	$ (1,633)				(1,633)
Ending balance (in shares) at Sep. 30, 2020	126,028,762	126,029,000
Balance at Sep. 30, 2020	$ 1,929,929	$ 1,260	$ 3,692,634	$ (1,740,670)	$ (24,993)	$ 1,698