Organization And Summary Of Significant Accounting Policies (Computation Of Basic And Diluted Earnings Per Share) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013		Jun. 30, 2012
Earnings Per Share, Basic and Diluted, by Common Class, Including Two Class Method [Line Items]
Net earnings attributable to NNN	$ 37,486	$ 33,505	$ 71,552		$ 63,337
Less: Excess of redemption value over carrying value of Series C preferred shares redeemed	0	0	0		(3,098)
Net earnings attributable to common stockholders	32,724	27,579	62,029		52,334
Less: Earnings attributable to unvested restricted shares	(130)	(180)	(231)		(312)
Net earnings used in basic earnings per share	32,594	27,399	61,798		52,022
Reallocated undistributed loss	0	0	0		0
Net earnings used in diluted earnings per share	32,594	27,399	61,798		52,022
Weighted average number of shares outstanding (in shares)	118,620,837	107,006,399	116,386,249		106,321,014
Less: Unvested restricted stock (in shares)	(469,370)	(696,804)	(427,465)		(631,329)
Less: Contingent shares (in shares)	(338,816)	(317,581)	(294,889)		(272,090)
Weighted average number of shares outstanding used in basic earnings per share (in shares)	117,812,651	105,992,014	115,663,895		105,417,595
Contingent shares (in shares)	0	0	0		12,735
Convertible notes payable (in shares)	2,882,355	1,310,445	2,570,706		1,259,319
Common stock options (in shares)	0	1,419	0		1,855
Directors' deferred fee plan (in shares)	170,519	155,115	169,088		152,576
Weighted average number of shares outstanding used in diluted earnings per share	120,865,525	107,458,993	118,403,689		106,844,080
Series C Depositary Share [Member]
Earnings Per Share, Basic and Diluted, by Common Class, Including Two Class Method [Line Items]
Less: Series C preferred stock dividends and Series D preferred stock dividends	0	0	0	[1]	(1,979)	[1]
Series D Depositary Share [Member]
Earnings Per Share, Basic and Diluted, by Common Class, Including Two Class Method [Line Items]
Less: Series C preferred stock dividends and Series D preferred stock dividends	$ (4,762)	$ (5,926)	$ (9,523)	[2]	$ (5,926)	[2]

[1] The Series C preferred stock was redeemed in March 2012. The dividends paid during the six months ended June 30, 2012 include accumulated and unpaid dividends through the redemption date.

[2] The Series D preferred stock has no maturity date and will remain outstanding unless redeemed.