Organization and Summary of Significant Accounting Policies (Computation of Basic and Diluted Earnings per Share) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Earnings Per Share [Abstract]
Net earnings attributable to NNN	$ 74,171	$ 73,023	$ 155,543	$ 129,610
Net earnings attributable to common stockholders	74,171	68,538	155,543	120,640
Less: Series F preferred stock dividends	0	(4,485)	0	(8,970)
Less: Earnings allocated to unvested restricted shares	(165)	(178)	(319)	(328)
Net earnings used in basic and diluted earnings per share	$ 74,006	$ 68,360	$ 155,224	$ 120,312
Basic and Diluted Weighted Average Shares Outstanding:
Weighted average number of shares outstanding	175,989,323	175,590,102	175,813,456	175,491,461
Less: Unvested restricted shares (in shares)	(310,844)	(341,467)	(300,810)	(315,209)
Less: Unvested contingent restricted shares (in shares)	(721,623)	(637,738)	(645,597)	(576,094)
Weighted Average Number of Shares Outstanding, Basic, Total	174,956,856,000	174,610,897,000	174,867,049,000	174,600,158,000
Other dilutive securities (in shares)	151,058,000	115,915,000	154,822,000	132,918,000
Weighted average number of shares outstanding used in diluted earnings per share (in shares)	175,107,914,000	174,726,812,000	175,021,871,000	174,733,076,000