Condensed Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013 Series E Depositary Share [Member]	Sep. 30, 2012 Series E Depositary Share [Member]	Sep. 30, 2013 Series C Depositary Share [Member]	Sep. 30, 2012 Series C Depositary Share [Member]	Sep. 30, 2013 Series D Depositary Share [Member]	Sep. 30, 2012 Series D Depositary Share [Member]
Cash flows from operating activities:
Earnings including noncontrolling interests	$ 115,851	$ 101,290
Adjustments to reconcile net earnings to net cash provided by operating activities:
Depreciation and amortization	72,423	54,926
Impairment losses and other charges, net of recoveries	4,003	9,043
Other than temporary valuation impairment	16	2,718
Amortization of notes payable discount	2,888	3,641
Amortization of debt costs	2,460	2,506
Amortization of mortgages payable premium	(43)	(14)
Amortization of deferred interest rate hedges	306	171
Equity in earnings of unconsolidated affiliate	0	(4,074)
Distributions received from unconsolidated affiliate	0	7,019
Gain on disposition of real estate	(4,402)	(4,446)
Gain on note receivable and property foreclosure	0	(198)
Performance incentive plan expense	6,531	7,010
Performance incentive plan payment	(2,139)	0
Change in operating assets and liabilities, net of assets acquired and liabilities assumed in business combinations:
Additions to held for sale real estate	(1,029)	(4,941)
Decrease in real estate leased to others using the direct financing method	1,230	1,222
Decrease in mortgages, notes and accrued interest receivable	688	37
Decrease in receivables	1,433	1,014
Increase in commercial mortgage residual interests	(80)	0
Increase in accrued rental income	(166)	(695)
Decrease in other assets	82	1,365
Increase in accrued interest payable	10,386	7,004
Increase (decrease) in other liabilities	4,061	(4,893)
Increase (decrease) in current tax liability	580	(7,192)
Net cash provided by operating activities	215,079	172,513
Cash flows from investing activities:
Proceeds from the disposition of real estate	52,092	32,371
Additions to real estate:
Accounted for using the operating method	(569,770)	(416,068)
Increase in mortgages and notes receivable	(3,086)	(8,768)
Principal payments on mortgages and notes receivable	14,225	10,668
Cash received from commercial mortgage residual interests	0	286
Payment of lease costs	(969)	(1,583)
Return of investment from unconsolidated affiliate	0	1,220
Other	(781)	(313)
Net cash used in investing activities	(508,289)	(382,187)
Cash flows from financing activities:
Proceeds from line of credit payable	445,000	685,900
Repayment of line of credit payable	(619,200)	(751,500)
Payment of interest rate hedge	(3,141)	0
Repayment of mortgages payable	(795)	(19,134)
Proceeds from notes payable	347,406	320,011
Repayment of notes payable	0	(50,000)
Repayment of notes payable – convertible	(246,797)	0
Payment of debt costs	(3,265)	(2,992)
Proceeds from issuance of common stock	263,366	119,259
Proceeds from issuance of Series D and E preferred stock			287,500	0			0	287,500
Stock issuance costs	(13,455)	(11,200)
Redemption of Series C preferred stock	0	(92,000)
Payment of Series C and Series D preferred stock dividends			(4,780)	0	0	(1,979)	(14,285)	(10,688)
Payment of common stock dividends	(139,890)	(124,139)
Net cash provided by financing activities	297,664	349,038
Net increase in cash and cash equivalents	4,454	139,364
Cash and cash equivalents at beginning of year	2,076	2,082
Cash and cash equivalents at end of year	6,530	141,446
Supplemental disclosure of cash flow information:
Interest paid, net of amount capitalized	50,667	50,872
Taxes paid	212	125
Supplemental disclosure of noncash investing and financing activities:
Issued 298,896 and 396,577 shares of restricted and unrestricted common stock in 2013 and 2012, respectively, pursuant to NNN’s performance incentive plan	8,218	8,576
Issued 12,186 and 12,373 shares of common stock in 2013 and 2012, respectively, to directors pursuant to NNN’s performance incentive plan	428	346
Issued 9,044 and 14,836 shares of common stock in 2013 and 2012, respectively, pursuant to NNN’s Deferred Director Fee Plan	118	223
Surrender of 241 and of 4,712 shares of restricted common stock in 2013 and 2012, respectively	7	113
Change in other comprehensive income	166	(382)
Change in lease classification (direct financing lease to operating lease)	0	757
Mortgages payable assumed in connection with real estate transactions	0	6,634
Mortgage receivable accepted in connection with real estate transactions	750	0
Real estate acquired in connection with mortgage receivable foreclosure	0	490
Real estate received in note receivable foreclosure	$ 0	$ 1,595