Real Estate (Rental Income) (Details) - USD ($)	3 Months Ended
Mar. 31, 2024	Mar. 31, 2023
Lease Income [Abstract]
Rental income from operating leases	$ 209,084,000	$ 198,183,000
Earned income from direct financing leases	119,000	144,000
Percentage rent	888,000	763,000
Rental revenues	210,091,000	199,090,000
Real estate expense reimbursement from tenants	4,734,000	4,540,000
Rental income	214,825,000	203,630,000
Rental income accrued during period	$ (36,000)	$ 469,000

Lease Income, Accrued During Period

No definition available.

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Balance Type:	debit
Period Type:	duration

- Definition

Operating Lease Income Statement, Real Estate Expense Reimbursement From Tenants

+ References

No definition available.

+ Details

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- Definition

Lease Income Before Real Estate Expense Reimbursements From Tenants.

+ References

No definition available.

+ Details

Name:	nnn_RentalRevenues
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Data Type:	xbrli:monetaryItemType
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Period Type:	duration

- Definition

Amount of lease income from variable lease payments, interest income on direct financing lease and after offset of loss recognized at commencement.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479773/842-30-50-5

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 270
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6A
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482964/270-10-50-6A

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 30
-Name Accounting Standards Codification
-Section 45
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479016/842-30-45-3

+ Details

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Balance Type:	credit
Period Type:	duration

- Definition

Amount of lease income from operating, direct financing, and sales-type leases. Includes, but is not limited to, variable lease payments, interest income, profit (loss) recognized at commencement, and lease payments paid and payable to lessor.

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- References

No definition available.

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

Amount of operating lease income from lease payments and variable lease payments paid and payable to lessor. Includes, but is not limited to, variable lease payments not included in measurement of lease receivable.

+ References

+ Details

Name:	us-gaap_OperatingLeaseLeaseIncome
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of variable lease payments from operating, direct financing, and sales-type leases, excluding amount included in measurement of lease receivable.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479773/842-30-50-5

+ Details

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Period Type:	duration