Condensed Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013 Series C Depositary Share [Member]	Jun. 30, 2012 Series C Depositary Share [Member]	Jun. 30, 2013 Series D Depositary Share [Member]	Jun. 30, 2012 Series D Depositary Share [Member]
Cash flows from operating activities:
Earnings including noncontrolling interests	$ 71,509	$ 63,299
Adjustments to reconcile net earnings to net cash provided by operating activities:
Performance incentive plan expense	4,843	3,889
Performance incentive plan payment	(2,139)	0
Depreciation and amortization	46,418	37,383
Impairment losses and other charges, net of recoveries	4,004	2,900
Amortization of notes payable discount	2,591	2,378
Amortization of debt costs	1,806	0
Amortization of mortgages payable premium	(28)	0
Amortization of deferred interest rate hedges	178	114
Equity in earnings of unconsolidated affiliate	0	(305)
Distributions received from unconsolidated affiliate	0	362
Gain on disposition of real estate	(3,174)	(2,752)
Gain on disposition of real estate	3,174	2,752
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)	(4,472)
Decrease in real estate leased to others using the direct financing method	810	807
Decrease (increase) in mortgages, notes and accrued interest receivable	217	(345)
Decrease (increase) in receivables	(331)	633
Decrease (increase) in accrued rental income	128	(218)
Decrease (increase) in other assets	(61)	487
Decrease in accrued interest payable	(250)	(668)
Decrease in other liabilities	(1,201)	(3,490)
Increase (decrease) in current tax liability	(102)	255
Net cash provided by operating activities	124,189	100,257
Cash flows from investing activities:
Proceeds from the disposition of real estate	17,088	12,024
Additions to real estate:
Accounted for using the operating method	(485,230)	(288,812)
Increase in mortgages and notes receivable	(1,060)	(7,861)
Principal payments on mortgages and notes receivable	3,160	3,085
Cash received from commercial mortgage residual interests	142	399
Payment of lease costs	(735)	(1,154)
Other	(117)	557
Net cash used in investing activities	(466,752)	(281,762)
Cash flows from financing activities:
Proceeds from line of credit payable	300,500	614,400
Repayment of line of credit payable	(474,700)	(537,400)
Payment of interest rate hedge	(3,141)	0
Repayment of mortgages payable	(526)	(680)
Proceeds from notes payable	347,406	0
Repayment of notes payable	0	(50,000)
Repayment of notes payable - convertible	(20,656)	0
Payment of debt costs	(3,183)	0
Proceeds from issuance of common stock	258,085	60,319
Proceeds from issuance of Series D and E preferred stock					0	287,500
Redemption of Series C preferred stock	0	(92,000)
Payment of Series C and Series D preferred stock dividends			0	(1,979)	(9,523)	(5,926)
Payment of common stock dividends	(90,943)	(81,511)
Stock issuance costs	(13,416)	(10,393)
Net cash provided by financing activities	577,403	182,330
Net increase in cash and cash equivalents	234,840	825
Cash and cash equivalents at beginning of year	2,076	2,082
Cash and cash equivalents at end of year	236,916	2,907
Supplemental disclosure of cash flow information:
Interest paid, net of amount capitalized	41,770	38,800
Taxes paid	117	78
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 7,774 and 8,389 shares of common stock in 2013 and 2012, respectively, to directors pursuant to NNN’s performance incentive plan	274	229
Issued 5,873 and 10,247 shares of common stock in 2013 and 2012, respectively, pursuant to NNN’s Deferred Director Fee Plan	75	149
Surrender of 241 and of 4,178 shares of restricted common stock in 2013 and 2012, respectively	7	98
Change in other comprehensive income	706	(326)
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