Schedule III - Real Estate and Accumulated Depreciation and Amortization Real Estate - Held for Sale (Details) (Assets Held-for-sale [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012
Chipotle Hadley Ma [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Amount of Encumbrances	$ 0
Real Estate and Accumulated Depreciation, Initial Cost of Land	45
Real Estate and Accumulated Depreciation, Initial Cost of Buildings and Improvements	0
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Improvements	0
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Carrying Costs	0
Real Estate and Accumulated Depreciation, Carrying Amount of Land	45	[1],[2]
Real Estate and Accumulated Depreciation, Carrying Amount of Buildings and Improvements	0	[1],[2]
Real Estate and Accumulated Depreciation, Carrying Amount of Land and Buildings and Improvements	45	[1],[2]
Mattress Firm Lancaster Oh [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Amount of Encumbrances	0
Real Estate and Accumulated Depreciation, Initial Cost of Land	550
Real Estate and Accumulated Depreciation, Initial Cost of Buildings and Improvements	0
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Improvements	0
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Carrying Costs	0
Real Estate and Accumulated Depreciation, Carrying Amount of Land	550	[1],[2]
Real Estate and Accumulated Depreciation, Carrying Amount of Buildings and Improvements	0	[1],[2]
Real Estate and Accumulated Depreciation, Carrying Amount of Land and Buildings and Improvements	550	[1],[2]
Power Center Midland Mi [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Amount of Encumbrances	0
Real Estate and Accumulated Depreciation, Initial Cost of Land	1,085
Real Estate and Accumulated Depreciation, Initial Cost of Buildings and Improvements	1,635
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Improvements	191
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Carrying Costs	0
Real Estate and Accumulated Depreciation, Carrying Amount of Land	1,085	[1],[2]
Real Estate and Accumulated Depreciation, Carrying Amount of Buildings and Improvements	1,826	[1],[2]
Real Estate and Accumulated Depreciation, Carrying Amount of Land and Buildings and Improvements	2,911	[1],[2]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	0
Power Center Topsham Me [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Amount of Encumbrances	0
Real Estate and Accumulated Depreciation, Initial Cost of Land	1,885
Real Estate and Accumulated Depreciation, Initial Cost of Buildings and Improvements	1,735
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Improvements	94
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Carrying Costs	0
Real Estate and Accumulated Depreciation, Carrying Amount of Land	1,885	[1],[2]
Real Estate and Accumulated Depreciation, Carrying Amount of Buildings and Improvements	155	[1],[2]
Real Estate and Accumulated Depreciation, Carrying Amount of Land and Buildings and Improvements	2,040	[1],[2]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	0
Power Center Irving Tx [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Amount of Encumbrances	0
Real Estate and Accumulated Depreciation, Initial Cost of Land	951
Real Estate and Accumulated Depreciation, Initial Cost of Buildings and Improvements	1,090
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Improvements	0
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Carrying Costs	0
Real Estate and Accumulated Depreciation, Carrying Amount of Land	951	[1],[2]
Real Estate and Accumulated Depreciation, Carrying Amount of Buildings and Improvements	1,063	[1],[2]
Real Estate and Accumulated Depreciation, Carrying Amount of Land and Buildings and Improvements	2,014	[1],[2]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	0
Power Center Waxahachie Tx [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Amount of Encumbrances	0
Real Estate and Accumulated Depreciation, Initial Cost of Land	1,249
Real Estate and Accumulated Depreciation, Initial Cost of Buildings and Improvements	1,097
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Improvements	0
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Carrying Costs	0
Real Estate and Accumulated Depreciation, Carrying Amount of Land	1,249	[1],[2]
Real Estate and Accumulated Depreciation, Carrying Amount of Buildings and Improvements	1,069	[1],[2]
Real Estate and Accumulated Depreciation, Carrying Amount of Land and Buildings and Improvements	2,318	[1],[2]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	0
Power Center Harlingen Tx1 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Amount of Encumbrances	0
Real Estate and Accumulated Depreciation, Initial Cost of Land	247
Real Estate and Accumulated Depreciation, Initial Cost of Buildings and Improvements	807
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Improvements	0
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Carrying Costs	0
Real Estate and Accumulated Depreciation, Carrying Amount of Land	247	[1],[2]
Real Estate and Accumulated Depreciation, Carrying Amount of Buildings and Improvements	807	[1],[2]
Real Estate and Accumulated Depreciation, Carrying Amount of Land and Buildings and Improvements	1,054	[1],[2]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	0
Power Center Harlingen Tx2 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Amount of Encumbrances	0
Real Estate and Accumulated Depreciation, Initial Cost of Land	749
Real Estate and Accumulated Depreciation, Initial Cost of Buildings and Improvements	1,238
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Improvements	0
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Carrying Costs	0
Real Estate and Accumulated Depreciation, Carrying Amount of Land	749	[1],[2]
Real Estate and Accumulated Depreciation, Carrying Amount of Buildings and Improvements	1,238	[1],[2]
Real Estate and Accumulated Depreciation, Carrying Amount of Land and Buildings and Improvements	1,987	[1],[2]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	0
Power Center Woodstock Ga [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Amount of Encumbrances	0
Real Estate and Accumulated Depreciation, Initial Cost of Land	261
Real Estate and Accumulated Depreciation, Initial Cost of Buildings and Improvements	701
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Improvements	0
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Carrying Costs	0
Real Estate and Accumulated Depreciation, Carrying Amount of Land	261	[1],[2]
Real Estate and Accumulated Depreciation, Carrying Amount of Buildings and Improvements	538	[1],[2]
Real Estate and Accumulated Depreciation, Carrying Amount of Land and Buildings and Improvements	799	[1],[2]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	0
Raising Canes Lancaster Oh [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Amount of Encumbrances	0
Real Estate and Accumulated Depreciation, Initial Cost of Land	550
Real Estate and Accumulated Depreciation, Initial Cost of Buildings and Improvements	0
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Improvements	0
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Carrying Costs	0
Real Estate and Accumulated Depreciation, Carrying Amount of Land	550	[1],[2]
Real Estate and Accumulated Depreciation, Carrying Amount of Buildings and Improvements	0	[1],[2]
Real Estate and Accumulated Depreciation, Carrying Amount of Land and Buildings and Improvements	550	[1],[2]
Roys Rancho Mirage Ca [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Amount of Encumbrances	0
Real Estate and Accumulated Depreciation, Initial Cost of Land	1,580
Real Estate and Accumulated Depreciation, Initial Cost of Buildings and Improvements	2,142
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Improvements	0
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Carrying Costs	0
Real Estate and Accumulated Depreciation, Carrying Amount of Land	1,580	[1],[2]
Real Estate and Accumulated Depreciation, Carrying Amount of Buildings and Improvements	2,142	[1],[2]
Real Estate and Accumulated Depreciation, Carrying Amount of Land and Buildings and Improvements	3,722	[1],[2]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	0
Tutor Time Elk Grove Ca [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Amount of Encumbrances	0
Real Estate and Accumulated Depreciation, Initial Cost of Land	1,216
Real Estate and Accumulated Depreciation, Initial Cost of Buildings and Improvements	2,786
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Improvements	9
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Carrying Costs	0
Real Estate and Accumulated Depreciation, Carrying Amount of Land	1,216	[1],[2]
Real Estate and Accumulated Depreciation, Carrying Amount of Buildings and Improvements	2,750	[1],[2]
Real Estate and Accumulated Depreciation, Carrying Amount of Land and Buildings and Improvements	3,966	[1],[2]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	0
Vacant Land Grand Prairie Tx [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Amount of Encumbrances	0
Real Estate and Accumulated Depreciation, Initial Cost of Land	387
Real Estate and Accumulated Depreciation, Initial Cost of Buildings and Improvements	0
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Improvements	0
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Carrying Costs	0
Real Estate and Accumulated Depreciation, Carrying Amount of Land	108	[1],[2]
Real Estate and Accumulated Depreciation, Carrying Amount of Buildings and Improvements	0	[1],[2]
Real Estate and Accumulated Depreciation, Carrying Amount of Land and Buildings and Improvements	108	[1],[2]
Vacant Land Topsham Me [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Amount of Encumbrances	0
Real Estate and Accumulated Depreciation, Initial Cost of Land	1,034
Real Estate and Accumulated Depreciation, Initial Cost of Buildings and Improvements	0
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Improvements	0
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Carrying Costs	0
Real Estate and Accumulated Depreciation, Carrying Amount of Land	293	[1],[2]
Real Estate and Accumulated Depreciation, Carrying Amount of Buildings and Improvements	0	[1],[2]
Real Estate and Accumulated Depreciation, Carrying Amount of Land and Buildings and Improvements	293	[1],[2]
Vacant Land Rockwall Tx [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Amount of Encumbrances	0
Real Estate and Accumulated Depreciation, Initial Cost of Land	900
Real Estate and Accumulated Depreciation, Initial Cost of Buildings and Improvements	0
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Improvements	0
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Carrying Costs	0
Real Estate and Accumulated Depreciation, Carrying Amount of Land	1,064	[1],[2]
Real Estate and Accumulated Depreciation, Carrying Amount of Buildings and Improvements	0	[1],[2]
Real Estate and Accumulated Depreciation, Carrying Amount of Land and Buildings and Improvements	1,064	[1],[2]
Vacant Land Fairfield Township Oh [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Amount of Encumbrances	0
Real Estate and Accumulated Depreciation, Initial Cost of Land	3,350
Real Estate and Accumulated Depreciation, Initial Cost of Buildings and Improvements	0
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Improvements	0
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Carrying Costs	0
Real Estate and Accumulated Depreciation, Carrying Amount of Land	1,868	[1],[2]
Real Estate and Accumulated Depreciation, Carrying Amount of Buildings and Improvements	0	[1],[2]
Real Estate and Accumulated Depreciation, Carrying Amount of Land and Buildings and Improvements	1,868	[1],[2]
Vacant Land Bonita Springs Fl [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Amount of Encumbrances	0
Real Estate and Accumulated Depreciation, Initial Cost of Land	112
Real Estate and Accumulated Depreciation, Initial Cost of Buildings and Improvements	0
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Improvements	0
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Carrying Costs	0
Real Estate and Accumulated Depreciation, Carrying Amount of Land	25	[1],[2]
Real Estate and Accumulated Depreciation, Carrying Amount of Buildings and Improvements	0	[1],[2]
Real Estate and Accumulated Depreciation, Carrying Amount of Land and Buildings and Improvements	25	[1],[2]
Vacant Land Lancaster Oh [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Amount of Encumbrances	0
Real Estate and Accumulated Depreciation, Initial Cost of Land	1,035
Real Estate and Accumulated Depreciation, Initial Cost of Buildings and Improvements	0
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Improvements	0
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Carrying Costs	0
Real Estate and Accumulated Depreciation, Carrying Amount of Land	100	[1],[2]
Real Estate and Accumulated Depreciation, Carrying Amount of Buildings and Improvements	0	[1],[2]
Real Estate and Accumulated Depreciation, Carrying Amount of Land and Buildings and Improvements	100	[1],[2]
Vacant Land Hadley Ma [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Amount of Encumbrances	0
Real Estate and Accumulated Depreciation, Initial Cost of Land	2,824
Real Estate and Accumulated Depreciation, Initial Cost of Buildings and Improvements	0
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Improvements	0
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Carrying Costs	0
Real Estate and Accumulated Depreciation, Carrying Amount of Land	1,753	[1],[2]
Real Estate and Accumulated Depreciation, Carrying Amount of Buildings and Improvements	0	[1],[2]
Real Estate and Accumulated Depreciation, Carrying Amount of Land and Buildings and Improvements	1,753	[1],[2]
Vacant Property Jacksonville Fl [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Amount of Encumbrances	0
Real Estate and Accumulated Depreciation, Initial Cost of Land	987
Real Estate and Accumulated Depreciation, Initial Cost of Buildings and Improvements	856
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Improvements	0
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Carrying Costs	0
Real Estate and Accumulated Depreciation, Carrying Amount of Land	283	[1],[2]
Real Estate and Accumulated Depreciation, Carrying Amount of Buildings and Improvements	170	[1],[2]
Real Estate and Accumulated Depreciation, Carrying Amount of Land and Buildings and Improvements	453	[1],[2]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	170
Real Estate and Accumulated Depreciation, Life Used for Depreciation	40 years
Vacant Property Woodstock Ga [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Amount of Encumbrances	0
Real Estate and Accumulated Depreciation, Initial Cost of Land	1,937
Real Estate and Accumulated Depreciation, Initial Cost of Buildings and Improvements	1,285
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Improvements	0
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Carrying Costs	0
Real Estate and Accumulated Depreciation, Carrying Amount of Land	1,363	[1],[2]
Real Estate and Accumulated Depreciation, Carrying Amount of Buildings and Improvements	210	[1],[2]
Real Estate and Accumulated Depreciation, Carrying Amount of Land and Buildings and Improvements	1,573	[1],[2]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	210
Real Estate and Accumulated Depreciation, Life Used for Depreciation	40 years
Vacant Property Hillman Mi [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Amount of Encumbrances	0
Real Estate and Accumulated Depreciation, Initial Cost of Land	167
Real Estate and Accumulated Depreciation, Initial Cost of Buildings and Improvements	823
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Improvements	0
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Carrying Costs	0
Real Estate and Accumulated Depreciation, Carrying Amount of Land	167	[1],[2]
Real Estate and Accumulated Depreciation, Carrying Amount of Buildings and Improvements	363	[1],[2]
Real Estate and Accumulated Depreciation, Carrying Amount of Land and Buildings and Improvements	530	[1],[2]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	64
Real Estate and Accumulated Depreciation, Life Used for Depreciation	40 years
Vacant Property Bellingham Wa [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Amount of Encumbrances	0
Real Estate and Accumulated Depreciation, Initial Cost of Land	1,237
Real Estate and Accumulated Depreciation, Initial Cost of Buildings and Improvements	1,260
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Improvements	0
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Carrying Costs	0
Real Estate and Accumulated Depreciation, Carrying Amount of Land	1,237	[1],[2]
Real Estate and Accumulated Depreciation, Carrying Amount of Buildings and Improvements	408	[1],[2]
Real Estate and Accumulated Depreciation, Carrying Amount of Land and Buildings and Improvements	1,645	[1],[2]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	96
Real Estate and Accumulated Depreciation, Life Used for Depreciation	30 years
Real Estate Held for Sale the Company has Invested in [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Amount of Encumbrances	0
Real Estate and Accumulated Depreciation, Initial Cost of Land	26,586
Real Estate and Accumulated Depreciation, Initial Cost of Buildings and Improvements	24,614
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Improvements	1,354
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Carrying Costs	0
Real Estate and Accumulated Depreciation, Carrying Amount of Land	20,877	[1],[2]
Real Estate and Accumulated Depreciation, Carrying Amount of Buildings and Improvements	19,088	[1],[2]
Real Estate and Accumulated Depreciation, Carrying Amount of Land and Buildings and Improvements	39,965	[1],[2]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	$ 540

[1] As of December 31, 2012, the leases are treated as either operating or financing leases for federal income tax purposes. As of December 31, 2012, the aggregate cost of the properties owned by NNN that are under operating leases were $4,020,556 and financing leases were $4,178.

[2] Transactions in real estate and accumulated depreciation during 2012, 2011, and 2010 are summarized as follows: 2012 2011 2010Land, buildings, and leasehold interests: Balance at the beginning of year$3,531,845 $2,774,947 $2,584,947Acquisitions, completed construction and tenant improvements701,054 772,073 248,438Disposition of land, buildings, and leasehold interests(77,219) (14,744) (58,438)Provision for loss on impairment of real estate10,312 431 —Balance at the close of year$4,145,368 $3,531,845 $2,774,947Accumulated depreciation and amortization: Balance at the beginning of year$270,621 $222,921 $183,949Disposition of land, buildings, and leasehold interests(6,980) (3,010) (2,071)Depreciation and amortization expense70,137 50,710 41,043Balance at the close of year$333,778 $270,621 $222,921