Organization and Summary of Significant Accounting Policies (Computation of Basic and Diluted Earnings per Share) (Details) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Basic and Diluted Earnings:
Net earnings attributable to NNN	$ 81,372	$ 56,587
Less: Series F preferred stock dividends	0	(4,485)
Net earnings attributable to common stockholders	81,372	52,102
Less: Earnings allocated to unvested restricted shares	(156)	(151)
Net earnings used in basic and diluted earnings per share	$ 81,216	$ 51,951
Basic and Diluted Weighted Average Shares Outstanding:
Weighted average number of shares outstanding (in shares)	175,635,634	175,391,723
Less: Unvested restricted shares (in shares)	(294,665)	(288,658)
Less: Unvested contingent restricted shares (in shares)	(568,726)	(513,765)
Weighted Average Number of Shares Outstanding, Basic, Total	174,772,243	174,589,300
Other dilutive securities (in shares)	138,970	125,317
Weighted average number of shares outstanding used in diluted earnings per share (in shares)	174,911,213	174,714,617