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		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012		Sep. 30, 2011
Earnings Per Share, Basic and Diluted, by Common Class, Including Two Class Method [Line Items]
Net earnings attributable to NNN	$ 38,015	$ 22,632	$ 101,353		$ 64,755
Less: Excess of redemption value over carrying value of preferred shares redeemed	0	0	(3,098)		0
Net earnings attributable to common stockholders	33,253	20,936	85,588		59,666
Less: Earnings attributable to unvested restricted shares	(215)	(160)	(525)		(442)
Net earnings used in basic earnings per share	33,038	20,776	85,063		59,224
Reallocated undistributed loss	(1)	(1)	(4)		(2)
Net earnings used in diluted earnings per share	33,037	20,775	85,059		59,222
Weighted average number of shares outstanding (in shares)	108,461,120	88,008,849	107,039,590		85,772,590
Less: Unvested restricted stock (in shares)	(696,270)	(647,617)	(652,890)		(623,818)
Less: Contingent shares (in shares)	(276,915)	(251,826)	(246,698)		(251,826)
Weighted average number of shares outstanding used in basic earnings per share (in shares)	107,487,935	87,109,406	106,140,002		84,896,946
Contingent shares (in shares)	0	0	8,459		0
Convertible notes payable (in shares)	2,692,153	516,775	1,787,275		385,942
Common stock options (in shares)	0	2,669	1,287		3,093
Directors' deferred fee plan (in shares)	159,617	159,400	154,886		152,889
Weighted average number of shares outstanding used in diluted earnings per share (in shares)	110,339,705	87,788,250	108,091,909		85,438,870
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	(1,696)	(1,979)	[1]	(5,089)	[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)	$ 0	$ (10,688)	[2]	$ 0	[2]

[1] The Series C preferred stock was redeemed in March 2012. The dividends paid during the quarter ended March 31, 2012 include accumulated and unpaid dividends through the redemption date.

[2] The Series D preferred stock dividends paid during the quarter ended June 30, 2012 include accumulated and unpaid dividends from the issuance date through the declaration date. The Series D preferred stock has no maturity date and will remain outstanding unless redeemed.