CONDENSED CONSOLIDATED STATEMENTS OF EQUITY - USD ($) $ in Thousands	Total	Series F Preferred Stock	Total  Stockholders’ Equity of NNN	Total  Stockholders’ Equity of NNN Series F Preferred Stock	Preferred Stock Series F Preferred Stock	Common Stock	Capital in Excess of Par Value	Accumulated Deficit	Accumulated Deficit Series F Preferred Stock	Accumulated Other Comprehensive Income (Loss)	Noncontrolling Interests
Balances at Dec. 31, 2019	$ 4,331,682		$ 4,331,675		$ 345,000	$ 1,718	$ 4,495,314	$ (499,229)		$ (11,128)	$ 7
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	167,509		167,512					167,512			(3)
Dividends declared and paid:
Preferred stock dividends declared and paid		$ (13,455)		$ (13,455)					$ (13,455)
Common stock dividends declared and paid	(262,066)		(262,066)			1	4,298	(266,365)
Issuance of common stock:
Director compensation	865		865			1	864
Stock purchase plan	238		238				238
ATM equity program	60,902		60,902			16	60,886
Restricted shares, net of forfeitures						3	(3)
Stock issuance costs	(1,230)		(1,230)				(1,230)
Amortization of deferred compensation	8,718		8,718				8,718
Amortization of interest rate hedges	1,663		1,663							1,663
Fair value of forward starting swaps	(7,617)		(7,617)							(7,617)
Balances at Sep. 30, 2020	4,287,209		4,287,205		345,000	1,739	4,569,085	(611,537)		(17,082)	4
Balances at Jun. 30, 2020	4,310,800		4,310,795		345,000	1,735	4,554,958	(573,174)		(17,724)	5
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	56,068		56,069					56,069			(1)
Dividends declared and paid:
Preferred stock dividends declared and paid		(4,485)		(4,485)					(4,485)
Common stock dividends declared and paid	(86,799)		(86,799)			1	3,147	(89,947)
Issuance of common stock:
Director compensation	269		269			1	268
Stock purchase plan	68		68				68
ATM equity program	8,139		8,139			2	8,137
Stock issuance costs	(484)		(484)				(484)
Amortization of deferred compensation	2,991		2,991				2,991
Amortization of interest rate hedges	642		642							642
Fair value of forward starting swaps
Balances at Sep. 30, 2020	4,287,209		4,287,205		345,000	1,739	4,569,085	(611,537)		(17,082)	4
Balances at Dec. 31, 2020	4,319,304		4,319,300		345,000	1,753	4,633,771	(644,779)		(16,445)	4
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	212,540		212,543					212,543			(3)
Dividends declared and paid:
Preferred stock dividends declared and paid		(13,455)		(13,455)					(13,455)
Common stock dividends declared and paid	(272,709)		(272,709)				1,841	(274,550)
Issuance of common stock:
Director compensation	840		840				840
Stock purchase plan	251		251				251
ATM equity program	1,234		1,234			1	1,233
Restricted shares, net of forfeitures						3	(3)
Stock issuance costs	(253)		(253)				(253)
Amortization of deferred compensation	11,481		11,481				11,481
Amortization of interest rate hedges	2,494		2,494							2,494
Fair value of forward starting swaps	(1,584)		(1,584)							(1,584)
Balances at Sep. 30, 2021	4,260,143		4,260,142		345,000	1,757	4,649,161	(720,241)		(15,535)	1
Balances at Jun. 30, 2021	4,270,878		4,270,876		345,000	1,757	4,644,593	(705,958)		(14,516)	2
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	82,932		82,933					82,933			(1)
Dividends declared and paid:
Preferred stock dividends declared and paid		$ (4,485)		$ (4,485)					$ (4,485)
Common stock dividends declared and paid	(92,097)		(92,097)				634	(92,731)
Issuance of common stock:
Director compensation	306		306				306
Stock purchase plan	86		86				86
Stock issuance costs	(51)		(51)				(51)
Amortization of deferred compensation	3,593		3,593				3,593
Amortization of interest rate hedges	565		565							565
Fair value of forward starting swaps	(1,584)		(1,584)							(1,584)
Balances at Sep. 30, 2021	$ 4,260,143		$ 4,260,142		$ 345,000	$ 1,757	$ 4,649,161	$ (720,241)		$ (15,535)	$ 1