Notes Payable and Derivatives - Summary of outstanding series of unsecured notes (Details) - USD ($) $ in Thousands		Dec. 31, 2024	Jun. 30, 2024
Debt Instrument [Line Items]
Long-term debt maturities for the next five years		$ 1,550,000
Notes Payable
Debt Instrument [Line Items]
Stated Rate			3.90%
2025 Notes
Debt Instrument [Line Items]
Principal	[1],[2],[3]	400,000
Discount	[1],[2],[3],[4]	964
Net Price	[1],[2],[3]	$ 399,036
Stated Rate	[1],[2],[3]	4.00%
Effective Rate	[1],[2],[3],[5]	4.029%
2026 Notes
Debt Instrument [Line Items]
Principal	[1],[3]	$ 350,000
Discount	[1],[3],[4]	3,860
Net Price	[1],[3]	$ 346,140
Stated Rate	[1],[3]	3.60%
Effective Rate	[1],[3],[5]	3.733%
2027 Notes
Debt Instrument [Line Items]
Principal	[1],[3]	$ 400,000
Discount	[1],[3],[4]	1,628
Net Price	[1],[3]	$ 398,372
Stated Rate	[1],[3]	3.50%
Effective Rate	[1],[3],[5]	3.548%
2028 Notes
Debt Instrument [Line Items]
Principal	[1],[3]	$ 400,000
Discount	[1],[3],[4]	2,848
Net Price	[1],[3]	$ 397,152
Stated Rate	[1],[3]	4.30%
Effective Rate	[1],[3],[5]	4.388%
2030 Notes
Debt Instrument [Line Items]
Principal	[1]	$ 400,000
Discount	[1],[4]	1,288
Net Price	[1]	$ 398,712
Stated Rate	[1]	2.50%
Effective Rate	[1],[5]	2.536%
2033 Notes
Debt Instrument [Line Items]
Principal		$ 500,000
Discount	[4]	11,620
Net Price		$ 488,380
Stated Rate		5.60%
Effective Rate	[5]	5.905%
2034 Notes
Debt Instrument [Line Items]
Principal		$ 500,000
Discount	[4]	6,160
Net Price		$ 493,840
Stated Rate		5.50%
Effective Rate	[5]	5.662%
2048 Notes
Debt Instrument [Line Items]
Principal		$ 300,000
Discount	[4]	4,239
Net Price		$ 295,761
Stated Rate		4.80%
Effective Rate	[5]	4.89%
2050 Notes
Debt Instrument [Line Items]
Principal		$ 300,000
Discount	[4]	6,066
Net Price		$ 293,934
Stated Rate		3.10%
Effective Rate	[5]	3.205%
April 2051
Debt Instrument [Line Items]
Principal		$ 450,000
Discount	[4]	8,406
Net Price		$ 441,594
Stated Rate		3.50%
Effective Rate	[5]	3.602%
2052 Notes
Debt Instrument [Line Items]
Principal	[1]	$ 450,000
Discount	[1],[4]	10,422
Net Price	[1]	$ 439,578
Stated Rate	[1]	3.00%
Effective Rate	[1],[5]	3.118%

[1] NNN entered into forward starting swaps which were hedging the risk of changes in forecasted interest payments on forecasted issuance of long-term debt. Upon the issuance of a series of unsecured notes, NNN terminated such derivatives, and the resulting fair value was deferred in other comprehensive income. The deferred liability (asset) is being amortized over the term of the respective notes using the effective interest method.

[2] NNN plans to use proceeds from the Credit Facility and/or potential debt or equity offerings to repay the outstanding debt.

[3] The aggregate principal balance of the unsecured note maturities for the next five years is $1,550,000.

[4] The note discounts are amortized to interest expense over the respective term of each debt obligation using the effective interest method.

[5] Includes the effects of the discount at issuance.