Income Taxes (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Taxes [Line Items]
GAAP basis financial statement net income/(loss)	$ (48,387,000)	$ 146,830,000	$ (1,153,000)
Depreciation and amortization expense recognized for financial reporting purposes in excess of amounts recognized for income tax purposes	93,791,000	96,694,000	75,969,000
Rental income accrued for income tax purposes less than amounts for financial reporting purposes	(18,817,000)	(26,211,000)	(18,798,000)
Net amortization of above/below-market lease intangibles for income tax purposes in excess of amounts for financial reporting purposes	(12,049,000)	(13,022,000)	(9,465,000)
Gain on disposal of property for financial reporting purposes in excess of amounts for income tax purposes	0	(137,871,000)	0
Other expenses, including impairment charges, for financial reporting purposes in excess of amounts for income tax purposes	40,173,000	30,310,000	51,095,000
Income tax basis net income, prior to dividends paid deduction	$ 60,984,000	$ 99,841,000	$ 100,512,000
Ordinary income	63.22%	82.85%	96.34%
Return of capital	34.69%	3.79%	3.66%
Capital gains	2.08%	13.36%	0.00%
Common stock dividends, percent	100.00%	100.00%	100.00%
Accrued interest and penalties related to uncertain tax positions	$ 0	$ 0
Piedmont Washington Properties, Inc
Income Taxes [Line Items]
Taxable income for subsidiary in excess of/(less than) amount for financial reporting purposes	6,212,000	3,111,000	$ 3,518,000
Piedmont Office Holdings, Inc
Income Taxes [Line Items]
Taxable income for subsidiary in excess of/(less than) amount for financial reporting purposes	$ 61,000	$ 0	$ (654,000)