Condensed Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
ASSETS
Accounted for using the operating method, net of accumulated depreciation and amortization	$ 3,485,819	$ 3,225,119
Accounted for using the direct financing method	24,954	26,518
Real estate, held for sale	40,351	36,105
Investment in unconsolidated affiliate	4,283	4,358
Mortgages, notes and accrued interest receivable, net of allowance	36,740	33,428
Commercial mortgage residual interests	12,395	15,299
Cash and cash equivalents	2,907	2,082
Receivables, net of allowance of $1,113 and $1,403, respectively	1,456	2,149
Accrued rental income, net of allowance of $3,086 and $4,870, respectively	25,330	25,187
Debt costs, net of accumulated amortization of $16,986 and $15,332, respectively	9,148	10,802
Other assets	60,607	53,382
Total assets	3,703,990	3,434,429
LIABILITIES AND EQUITY
Line of credit payable	142,600	65,600
Mortgages payable, including unamortized premium of $216 and $0, respectively	29,341	23,171
Notes payable - convertible, net of unamortized discount of $4,256 and $6,363, respectively	357,479	355,371
Notes payable, net of unamortized discount of $4,763 and $5,033, respectively	845,237	894,967
Accrued interest payable	14,440	15,108
Other liabilities	87,483	76,336
Total liabilities	1,476,580	1,430,553
Stockholders' equity:
Common stock, $0.01 par value. Authorized 190,000,000 shares; 107,449,071 and 104,754,859 shares issued and outstanding, respectively	1,076	1,049
Excess stock, $0.01 par value. Authorized 205,000,000 shares; none issued or outstanding	0	0
Capital in excess of par value	2,015,121	1,958,225
Retained earnings (loss)	(74,123)	(44,946)
Accumulated other comprehensive income (loss)	(3,504)	(3,830)
Total stockholders' equity of NNN	2,226,070	2,002,498
Noncontrolling interests	1,340	1,378
Total equity	2,227,410	2,003,876
Total liabilities and equity	3,703,990	3,434,429
Series D Depositary Share [Member]
Stockholders' equity:
Series D, 11,500,000 depositary shares issued and outstanding, at stated liquidation value of $25 per share	287,500	0
Series C, 3,680,000 depositary shares issued and outstanding, at stated liquidation value of $25 per share	287,500	0
Series C Depositary Share [Member]
Stockholders' equity:
Series D, 11,500,000 depositary shares issued and outstanding, at stated liquidation value of $25 per share	0	92,000
Series C, 3,680,000 depositary shares issued and outstanding, at stated liquidation value of $25 per share	$ 0	$ 92,000