Guarantor and Non-Guarantor Financial Information - Condensed Consolidated Statements of Income (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Revenues:
Rental income	$ 117,807	$ 110,904
Tenant reimbursements	31,390	24,929
Property management fee revenue	562	487
Total revenues	149,759	136,320
Expenses:
Property operating costs	64,236	58,271
Depreciation	36,232	33,644
Amortization	14,670	14,573
General and administrative	6,407	4,555
Operating Expenses	121,545	111,043
Real estate operating income	28,214	25,277
Other income (expense):
Interest expense	(19,016)	(18,926)
Other income/(expense)	(181)	(90)
Net recoveries from casualty events and litigation settlements	0	3,042
Equity in income/(loss) of unconsolidated joint ventures	159	(266)
Nonoperating Income (Expense)	(19,038)	(16,240)
Income from continuing operations	9,176	9,037
Discontinued operations:
Operating income	0	466
Loss on sale of real estate assets, net	0	(106)
Income from discontinued operations	0	360
Gain on sale of real estate assets, net	10,073	0
Net income	19,249	9,397
Less: Net income attributable to noncontrolling interest	(4)	(4)
Net income attributable to Piedmont	19,245	9,393	43,348
Issuer [Member]
Revenues:
Rental income	18,937	17,400
Tenant reimbursements	4,246	3,861
Property management fee revenue	0	0
Total revenues	23,183	21,261
Expenses:
Property operating costs	10,661	10,044
Depreciation	5,803	5,840
Amortization	1,254	1,111
General and administrative	6,200	4,469
Operating Expenses	23,918	21,464
Real estate operating income	(735)	(203)
Other income (expense):
Interest expense	(13,188)	(9,120)
Other income/(expense)	2,766	2,762
Net recoveries from casualty events and litigation settlements		1,351
Equity in income/(loss) of unconsolidated joint ventures	159	(266)
Nonoperating Income (Expense)	(10,263)	(5,273)
Income from continuing operations	(10,998)	(5,476)
Discontinued operations:
Operating income	0	480
Loss on sale of real estate assets, net		(106)
Income from discontinued operations	0	374
Gain on sale of real estate assets, net	10,073
Net income	(925)	(5,102)
Less: Net income attributable to noncontrolling interest	0	0
Net income attributable to Piedmont	(925)	(5,102)
Guarantor [Member]
Revenues:
Rental income	0	0
Tenant reimbursements	0	0
Property management fee revenue	0	0
Total revenues	0	0
Expenses:
Property operating costs	0	0
Depreciation	0	0
Amortization	0	0
General and administrative	111	77
Operating Expenses	111	77
Real estate operating income	(111)	(77)
Other income (expense):
Interest expense	0	0
Other income/(expense)	0	35
Net recoveries from casualty events and litigation settlements		0
Equity in income/(loss) of unconsolidated joint ventures	0	0
Nonoperating Income (Expense)	0	35
Income from continuing operations	(111)	(42)
Discontinued operations:
Operating income	0	0
Loss on sale of real estate assets, net		0
Income from discontinued operations	0	0
Gain on sale of real estate assets, net	0
Net income	(111)	(42)
Less: Net income attributable to noncontrolling interest	0	0
Net income attributable to Piedmont	(111)	(42)
Non-Guarantor Subsidiaries [Member]
Revenues:
Rental income	99,577	95,157
Tenant reimbursements	27,272	21,179
Property management fee revenue	4,439	4,171
Total revenues	131,288	120,507
Expenses:
Property operating costs	58,494	53,878
Depreciation	30,429	27,804
Amortization	13,416	13,462
General and administrative	7,724	5,961
Operating Expenses	110,063	101,105
Real estate operating income	21,225	19,402
Other income (expense):
Interest expense	(8,949)	(12,939)
Other income/(expense)	174	246
Net recoveries from casualty events and litigation settlements		1,691
Equity in income/(loss) of unconsolidated joint ventures	0	0
Nonoperating Income (Expense)	(8,775)	(11,002)
Income from continuing operations	12,450	8,400
Discontinued operations:
Operating income	0	(14)
Loss on sale of real estate assets, net		0
Income from discontinued operations	0	(14)
Gain on sale of real estate assets, net	0
Net income	12,450	8,386
Less: Net income attributable to noncontrolling interest	(4)	(4)
Net income attributable to Piedmont	12,446	8,382
Eliminations [Member]
Revenues:
Rental income	(707)	(1,653)
Tenant reimbursements	(128)	(111)
Property management fee revenue	(3,877)	(3,684)
Total revenues	(4,712)	(5,448)
Expenses:
Property operating costs	(4,919)	(5,651)
Depreciation	0	0
Amortization	0	0
General and administrative	(7,628)	(5,952)
Operating Expenses	(12,547)	(11,603)
Real estate operating income	7,835	6,155
Other income (expense):
Interest expense	3,121	3,133
Other income/(expense)	(3,121)	(3,133)
Net recoveries from casualty events and litigation settlements		0
Equity in income/(loss) of unconsolidated joint ventures	0	0
Nonoperating Income (Expense)	0	0
Income from continuing operations	7,835	6,155
Discontinued operations:
Operating income	0	0
Loss on sale of real estate assets, net		0
Income from discontinued operations	0	0
Gain on sale of real estate assets, net	0
Net income	7,835	6,155
Less: Net income attributable to noncontrolling interest	0	0
Net income attributable to Piedmont	$ 7,835	$ 6,155