Guarantor and Non-Guarantor Financial Information - Condensed Consolidated Balance Sheets (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015	Jun. 30, 2015	Dec. 31, 2014
Assets:
Land	$ 656,240	$ 676,091
Buildings and improvements, less accumulated depreciation	2,780,501	2,837,463
Intangible lease assets, less accumulated amortization	71,794	84,663
Construction in progress	25,187	20,975
Real estate assets held for sale, net	69,766	76,614
Total real estate assets	3,603,488	3,695,806
Investments in and amounts due from unconsolidated joint ventures	7,413	7,577
Cash and cash equivalents	21,109	5,441	$ 8,997	$ 12,306
Tenant and straight-line rent receivables, net	175,965	173,732
Advances to affiliates	0	0
Investment in subsidiary	0	0
Note receivable	0	45,400
Prepaid expenses, restricted cash, escrows, and other assets	40,326	29,951
Goodwill	180,097	180,097
Deferred lease costs, net	261,340	288,041
Other assets held for sale, net	8,761	8,490
Total assets	4,298,499	4,434,535
Liabilities:
Debt, net	1,884,314	2,029,510
Accounts payable, accrued expenses, and accrued capital expenditures	122,387	128,465
Advances from affiliates	0	0
Deferred income	24,036	27,270
Intangible lease liabilities, net	38,970	42,853
Interest rate swaps	22,079	9,993
Total liabilities	2,091,786	2,238,091
Stockholders’ Equity:
Common stock	1,452	1,455
Additional paid-in capital	3,671,475	3,669,977
Cumulative distributions in excess of earnings	(1,456,129)	(1,477,674)
Other comprehensive income/(loss)	(11,110)	1,661
Piedmont stockholders’ equity	2,205,688	2,195,419
Noncontrolling interest	1,025	1,025
Total stockholders’ equity	2,206,713	2,196,444		2,312,015
Total liabilities and stockholders’ equity	4,298,499	4,434,535
Eliminations [Member]
Assets:
Land	0	0
Buildings and improvements, less accumulated depreciation	(300)	(300)
Intangible lease assets, less accumulated amortization	0	0
Construction in progress	0	0
Real estate assets held for sale, net	0	0
Total real estate assets	(300)	(300)
Investments in and amounts due from unconsolidated joint ventures	0	0
Cash and cash equivalents	0	0	0	0
Tenant and straight-line rent receivables, net	0	0
Advances to affiliates	(7,398,607)	(7,325,136)
Investment in subsidiary	(3,691,746)	(3,752,709)
Note receivable	(103,639)	(113,240)
Prepaid expenses, restricted cash, escrows, and other assets	(1,657)	(1,258)
Goodwill	0	0
Deferred lease costs, net	0	0
Other assets held for sale, net	0	0
Total assets	(11,195,949)	(11,192,643)
Liabilities:
Debt, net	(103,639)	(113,240)
Accounts payable, accrued expenses, and accrued capital expenditures	(1,657)	(1,258)
Advances from affiliates	(7,488,637)	(7,402,632)
Deferred income	0	0
Intangible lease liabilities, net	0	0
Interest rate swaps	0	0
Total liabilities	(7,593,933)	(7,517,130)
Stockholders’ Equity:
Common stock	0	0
Additional paid-in capital	(3,691,746)	(3,752,710)
Cumulative distributions in excess of earnings	89,730	77,197
Other comprehensive income/(loss)	0	0
Piedmont stockholders’ equity	(3,602,016)	(3,675,513)
Noncontrolling interest	0	0
Total stockholders’ equity	(3,602,016)	(3,675,513)
Total liabilities and stockholders’ equity	(11,195,949)	(11,192,643)
Issuer [Member]
Assets:
Land	48,213	54,459
Buildings and improvements, less accumulated depreciation	242,179	270,057
Intangible lease assets, less accumulated amortization	997	1,268
Construction in progress	387	240
Real estate assets held for sale, net	69,766	76,614
Total real estate assets	361,542	402,638
Investments in and amounts due from unconsolidated joint ventures	7,413	7,577
Cash and cash equivalents	16,270	2,174	6,164	8,143
Tenant and straight-line rent receivables, net	20,448	23,738
Advances to affiliates	6,115,364	6,073,606
Investment in subsidiary	0	0
Note receivable	89,350	134,750
Prepaid expenses, restricted cash, escrows, and other assets	17,069	7,091
Goodwill	180,097	180,097
Deferred lease costs, net	18,115	20,939
Other assets held for sale, net	8,761	8,490
Total assets	6,834,429	6,861,100
Liabilities:
Debt, net	1,522,642	1,552,007
Accounts payable, accrued expenses, and accrued capital expenditures	17,525	18,954
Advances from affiliates	641,314	580,526
Deferred income	4,077	5,905
Intangible lease liabilities, net	0	0
Interest rate swaps	22,079	9,993
Total liabilities	2,207,637	2,167,385
Stockholders’ Equity:
Common stock	0	0
Additional paid-in capital	3,687,562	3,748,524
Cumulative distributions in excess of earnings	950,340	943,530
Other comprehensive income/(loss)	(11,110)	1,661
Piedmont stockholders’ equity	4,626,792	4,693,715
Noncontrolling interest	0	0
Total stockholders’ equity	4,626,792	4,693,715
Total liabilities and stockholders’ equity	6,834,429	6,861,100
Guarantor [Member]
Assets:
Land	0	0
Buildings and improvements, less accumulated depreciation	0	0
Intangible lease assets, less accumulated amortization	0	0
Construction in progress	0	0
Real estate assets held for sale, net	0	0
Total real estate assets	0	0
Investments in and amounts due from unconsolidated joint ventures	0	0
Cash and cash equivalents	150	150	150	1,790
Tenant and straight-line rent receivables, net	0	0
Advances to affiliates	1,283,243	1,251,530
Investment in subsidiary	3,691,562	3,752,523
Note receivable	0	0
Prepaid expenses, restricted cash, escrows, and other assets	75	0
Goodwill	0	0
Deferred lease costs, net	0	0
Other assets held for sale, net	0	0
Total assets	4,975,030	5,004,203
Liabilities:
Debt, net	0	0
Accounts payable, accrued expenses, and accrued capital expenditures	573	580
Advances from affiliates	5,071,390	5,033,266
Deferred income	0	0
Intangible lease liabilities, net	0	0
Interest rate swaps	0	0
Total liabilities	5,071,963	5,033,846
Stockholders’ Equity:
Common stock	1,452	1,455
Additional paid-in capital	3,674,348	3,672,849
Cumulative distributions in excess of earnings	(3,772,733)	(3,703,947)
Other comprehensive income/(loss)	0	0
Piedmont stockholders’ equity	(96,933)	(29,643)
Noncontrolling interest	0	0
Total stockholders’ equity	(96,933)	(29,643)
Total liabilities and stockholders’ equity	4,975,030	5,004,203
Non-Guarantor Subsidiaries [Member]
Assets:
Land	608,027	621,632
Buildings and improvements, less accumulated depreciation	2,538,622	2,567,706
Intangible lease assets, less accumulated amortization	70,797	83,395
Construction in progress	24,800	20,735
Real estate assets held for sale, net	0	0
Total real estate assets	3,242,246	3,293,468
Investments in and amounts due from unconsolidated joint ventures	0	0
Cash and cash equivalents	4,689	3,117	$ 2,683	$ 2,373
Tenant and straight-line rent receivables, net	155,517	149,994
Advances to affiliates	0	0
Investment in subsidiary	184	186
Note receivable	14,289	23,890
Prepaid expenses, restricted cash, escrows, and other assets	24,839	24,118
Goodwill	0	0
Deferred lease costs, net	243,225	267,102
Other assets held for sale, net	0	0
Total assets	3,684,989	3,761,875
Liabilities:
Debt, net	465,311	590,743
Accounts payable, accrued expenses, and accrued capital expenditures	105,946	110,189
Advances from affiliates	1,775,933	1,788,840
Deferred income	19,959	21,365
Intangible lease liabilities, net	38,970	42,853
Interest rate swaps	0	0
Total liabilities	2,406,119	2,553,990
Stockholders’ Equity:
Common stock	0	0
Additional paid-in capital	1,311	1,314
Cumulative distributions in excess of earnings	1,276,534	1,205,546
Other comprehensive income/(loss)	0	0
Piedmont stockholders’ equity	1,277,845	1,206,860
Noncontrolling interest	1,025	1,025
Total stockholders’ equity	1,278,870	1,207,885
Total liabilities and stockholders’ equity	$ 3,684,989	$ 3,761,875