Guarantor and Non-Guarantor Financial Information - Statements of Income (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenues:
Rental and tenant reimbursement revenue									$ 511,905	$ 504,410	$ 553,264
Total revenues	$ 134,153	$ 135,421	$ 130,668	$ 132,936	$ 137,185	$ 129,708	$ 129,174	$ 129,900	533,178	525,967	574,173
Expenses:
Property operating costs									211,380	209,338	222,441
Depreciation									106,015	107,956	119,288
Amortization									76,666	63,295	75,367
Impairment loss on real estate assets									8,953	0	46,461
General and administrative									37,895	29,713	29,319
Expenses									440,909	410,302	492,876
Other income (expense):
Interest expense									(61,594)	(61,023)	(68,124)
Other income/(expense)									1,571	1,638	657
Equity in income of unconsolidated joint ventures									0	0	3,845
Loss on extinguishment of debt									0	(1,680)	0
Gain on sale of real estate assets, net	157,640	32	1,451	37,887	30,505	0	(23)	45,209	197,010	75,691	115,874
Nonoperating Income (Expense)									136,987	14,626	52,252
Income/(loss) before consolidated subsidiaries									229,256	130,291
Income from subsidiaries									0	0
Net income/(loss)	162,476	8,419	8,152	50,209	45,409	16,114	10,940	57,828	229,256	130,291	133,549
Net loss applicable to noncontrolling interest									5	5	15
Net income applicable to Piedmont	$ 162,478	$ 8,422	$ 8,153	$ 50,208	$ 45,410	$ 16,114	$ 10,942	$ 57,830	229,261	130,296	133,564
Eliminations
Revenues:
Rental and tenant reimbursement revenue									(2,834)	(2,473)	(2,265)
Total revenues									(18,798)	(18,141)	(18,735)
Expenses:
Property operating costs									(18,798)	(18,141)	(18,735)
Depreciation									0	0	0
Amortization									0	0	0
Impairment loss on real estate assets									0		0
General and administrative									0	0	0
Expenses									(18,798)	(18,141)	(18,735)
Other income (expense):
Interest expense									7,535	7,630	15,360
Other income/(expense)									(7,535)	(7,630)	(15,360)
Equity in income of unconsolidated joint ventures											0
Loss on extinguishment of debt										0
Gain on sale of real estate assets, net									0	0	0
Nonoperating Income (Expense)									0	0	0
Income/(loss) before consolidated subsidiaries									0	0
Income from subsidiaries									(484,804)	(309,233)
Net income/(loss)									(484,804)	(309,233)	0
Net loss applicable to noncontrolling interest									0	0	0
Net income applicable to Piedmont									(484,804)	(309,233)	0
Piedmont (Parent) (Guarantor) | Reportable Legal Entities
Revenues:
Rental and tenant reimbursement revenue									0	0	0
Total revenues									0	0	0
Expenses:
Property operating costs									0	0	0
Depreciation									0	0	0
Amortization									0	0	0
Impairment loss on real estate assets									0		0
General and administrative									218	289	347
Expenses									218	289	347
Other income (expense):
Interest expense									0	0	0
Other income/(expense)									0	0	0
Equity in income of unconsolidated joint ventures											0
Loss on extinguishment of debt										0
Gain on sale of real estate assets, net									0	0	0
Nonoperating Income (Expense)									0	0	0
Income/(loss) before consolidated subsidiaries									(218)	(289)
Income from subsidiaries									229,479	130,585
Net income/(loss)									229,261	130,296	(347)
Net loss applicable to noncontrolling interest									0	0	0
Net income applicable to Piedmont									229,261	130,296	(347)
Piedmont OP (the Issuer) | Reportable Legal Entities
Revenues:
Rental and tenant reimbursement revenue									46,669	44,710	54,109
Total revenues									46,827	44,840	54,253
Expenses:
Property operating costs									21,314	19,583	22,805
Depreciation									12,171	11,514	12,995
Amortization									1,940	1,990	3,049
Impairment loss on real estate assets									7,000		87
General and administrative									6,716	6,576	6,443
Expenses									49,141	39,663	45,379
Other income (expense):
Interest expense									(54,721)	(54,095)	(56,769)
Other income/(expense)									188	144	9,168
Equity in income of unconsolidated joint ventures											3,845
Loss on extinguishment of debt										(1,680)
Gain on sale of real estate assets, net									113	1,417	6,431
Nonoperating Income (Expense)									(54,420)	(54,214)	(37,325)
Income/(loss) before consolidated subsidiaries									(56,734)	(49,037)
Income from subsidiaries									255,325	178,648
Net income/(loss)									198,591	129,611	(28,451)
Net loss applicable to noncontrolling interest									0	0	0
Net income applicable to Piedmont									198,591	129,611	(28,451)
Non-Guarantor Subsidiaries | Reportable Legal Entities
Revenues:
Rental and tenant reimbursement revenue									468,070	462,173	501,420
Total revenues									505,149	499,268	538,655
Expenses:
Property operating costs									208,864	207,896	218,371
Depreciation									93,844	96,442	106,293
Amortization									74,726	61,305	72,318
Impairment loss on real estate assets									1,953		46,374
General and administrative									30,961	22,848	22,529
Expenses									410,348	388,491	465,885
Other income (expense):
Interest expense									(14,408)	(14,558)	(26,715)
Other income/(expense)									8,918	9,124	6,849
Equity in income of unconsolidated joint ventures											0
Loss on extinguishment of debt										0
Gain on sale of real estate assets, net									196,897	74,274	109,443
Nonoperating Income (Expense)									191,407	68,840	89,577
Income/(loss) before consolidated subsidiaries									286,208	179,617
Income from subsidiaries									0	0
Net income/(loss)									286,208	179,617	162,347
Net loss applicable to noncontrolling interest									5	5	15
Net income applicable to Piedmont									286,213	179,622	162,362
Management Service
Revenues:
Property management fee revenue									3,398	1,450	1,735
Management Service | Eliminations
Revenues:
Property management fee revenue									(15,964)	(15,668)	(16,470)
Management Service | Piedmont (Parent) (Guarantor) | Reportable Legal Entities
Revenues:
Property management fee revenue									0	0	0
Management Service | Piedmont OP (the Issuer) | Reportable Legal Entities
Revenues:
Property management fee revenue									0	0	0
Management Service | Non-Guarantor Subsidiaries | Reportable Legal Entities
Revenues:
Property management fee revenue									19,362	17,118	18,205
Other property related income
Revenues:
Property management fee revenue									17,875	20,107	19,174
Other property related income | Eliminations
Revenues:
Property management fee revenue									0	0	0
Other property related income | Piedmont (Parent) (Guarantor) | Reportable Legal Entities
Revenues:
Property management fee revenue									0	0	0
Other property related income | Piedmont OP (the Issuer) | Reportable Legal Entities
Revenues:
Property management fee revenue									158	130	144
Other property related income | Non-Guarantor Subsidiaries | Reportable Legal Entities
Revenues:
Property management fee revenue									$ 17,717	$ 19,977	$ 19,030