Condensed Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012 Series C Depositary Share [Member]	Jun. 30, 2011 Series C Depositary Share [Member]	Jun. 30, 2012 Series D Depositary Share [Member]	Jun. 30, 2011 Series D Depositary Share [Member]
Cash flows from operating activities:
Earnings including noncontrolling interests	$ 63,299	$ 42,123
Adjustments to reconcile net earnings to net cash provided by operating activities:
Performance incentive plan expense	3,889	3,297
Depreciation and amortization	37,383	27,678
Impairment losses and other charges	380	0
Impairment - commercial mortgage residual interests valuation	2,718	396
Amortization of notes payable discount	2,378	3,335
Amortization of deferred interest rate hedges	114	(85)
Equity in earnings of unconsolidated affiliate	(305)	(213)
Distributions received from unconsolidated affiliate	362	286
Gain on disposition of real estate portfolio	(2,752)	(132)
Gain on note receivable and property foreclosure	(198)	0
Other	0	82
Change in operating assets and liabilities, net of assets acquired and liabilities assumed in business combinations:
Additions to held for sale real estate	(4,472)	(212)
Proceeds from disposition of held for sale real estate	0	1,058
Decrease in real estate leased to others using the direct financing method	807	802
Increase in work in process	(889)	(575)
Increase in mortgages, notes and accrued interest receivable	(345)	(88)
Decrease in receivables	633	998
Decrease (increase) in commercial mortgage residual interests	399	(127)
Decrease (increase) in accrued rental income	(218)	149
Decrease (increase) in other assets	487	(19)
Decrease in accrued interest payable	(668)	(57)
Decrease in other liabilities	(3,490)	(1,631)
Increase in current tax liability	255	794
Net cash provided by operating activities	99,767	77,859
Cash flows from investing activities:
Proceeds from the disposition of real estate, Investment Portfolio	12,024	807
Additions to real estate:
Accounted for using the operating method	(287,923)	(111,673)
Accounted for using the direct financing method	0	(1,747)
Increase in mortgages and notes receivable	(7,861)	(4,090)
Principal payments on mortgages and notes receivable	3,085	2,107
Payment of lease costs	(1,154)	(672)
Other	557	402
Net cash used in investing activities	(281,272)	(114,866)
Cash flows from financing activities:
Proceeds from line of credit payable	614,400	328,800
Repayment of line of credit payable	(537,400)	(270,600)
Payment of interest rate hedge	0	(5,300)
Repayment of notes payable	(50,000)	0
Payment of debt costs	0	(2,920)
Repayment of mortgages payable	(680)	(541)
Proceeds from issuance of common stock	60,319	56,391
Proceeds from issuance of preferred stock	287,500	0
Redemption of preferred stock	(92,000)	0
Payment of Series C and Series D preferred stock dividends			(1,979)	(3,392)	(5,926)	0
Payment of common stock dividends	(81,511)	(63,887)
Noncontrolling interest distributions	0	(45)
Noncontrolling interest contributions	0	41
Stock issuance costs	(10,393)	0
Net cash provided by financing activities	182,330	38,547
Net increase in cash and cash equivalents	825	1,540
Cash and cash equivalents at beginning of year	2,082	2,048
Cash and cash equivalents at end of year	2,907	3,588
Supplemental disclosure of cash flow information:
Interest paid, net of amount capitalized	38,800	33,230
Taxes paid (received)	78	(487)
Supplemental disclosure of non-cash investing and financing activities:
Issued 396,577 and 139,351 shares of restricted and unrestricted common stock in 2012 and 2011, respectively, pursuant to NNN's performance incentive plan	8,576	3,407
Issued 8,389 and 4,623 shares of common stock in 2012 and 2011, respectively, to directors pursuant to NNN's performance incentive plan	229	118
Issued 10,247 and 13,879 shares of common stock in 2012 and 2011, respectively, pursuant to NNN's Deferred Director Fee Plan	149	245
Surrender of 4,178 and 4,494 shares of restricted stock in 2012 and 2011, respectively	98	94
Change in other comprehensive income	(326)	(4,730)
Change in lease classification (direct financing lease to operating lease)	757	2,243
Mortgage payable assumed in connection with real estate transaction	6,634	0
Real estate acquired in connection with mortgage receivable foreclosure	490	0
Real estate received in note receivable foreclosure	$ 1,595	$ 0