Condensed Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
ASSETS
Accounted for using the operating method, net of accumulated depreciation and amortization	$ 3,801,517	$ 3,788,053
Accounted for using the direct financing method	22,817	23,217
Real estate held for sale	23,492	23,537
Mortgages, notes and accrued interest receivable	26,884	27,770
Commercial mortgage residual interests	13,719	13,096
Cash and cash equivalents	3,442	2,076
Receivables, net of allowance of $1,353 and $855, respectively	3,260	3,112
Accrued rental income, net of allowance of $3,154 and $3,270, respectively	26,161	25,458
Debt costs, net of accumulated amortization of $18,002 and $17,965, respectively	11,874	12,781
Other assets	68,624	68,926
Total assets	4,001,790	3,988,026
Liabilities:
Line of credit payable	59,400	174,200
Mortgages payable, including unamortized premium of $173 and $187, respectively	10,328	10,602
Notes payable – convertible, net of unamortized discount of $951 and $2,072, respectively	222,084	236,500
Notes payable, net of unamortized discount of $9,103 and $9,338, respectively	1,165,897	1,165,662
Accrued interest payable	28,130	17,527
Other liabilities	73,191	85,950
Total liabilities	1,559,030	1,690,441
Stockholders’ equity:
Common stock, $0.01 par value. Authorized 375,000,000 shares; 116,891,268 and 111,554,997 shares issued and outstanding, respectively	1,171	1,117
Excess stock, $0.01 par value. Authorized 390,000,000 shares; none issued or outstanding	0	0
Capital in excess of par value	2,260,488	2,101,002
Retained earnings (deficit)	(105,969)	(90,952)
Accumulated other comprehensive income (loss)	(1,567)	(2,382)
Total stockholders’ equity of NNN	2,441,623	2,296,285
Noncontrolling interests	1,137	1,300
Total equity	2,442,760	2,297,585
Total liabilities and equity	4,001,790	3,988,026
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	$ 287,500