XML 124 R90.htm IDEA: XBRL DOCUMENT v3.25.0.1

Investments and Notes Receivable - Debt Securities, Available-for-Sale, Unrealized Loss Position, Fair Value (Details)	Dec. 31, 2024 USD ($)
Debt Securities, Available-for-Sale, Unrealized Loss Position [Line Items]
Asset -backed securities unrealized loss position not due to credit loss	$ 0
Debt Securities, Available-for-Sale, Unrealized Loss Position [Abstract]
Available-for-sale asset-backed securities, unrealized loss position less than 12 months, unrealized loss	(141,000)
Available-for-sale asset-backed securities, unrealized loss position 12 months or more, unrealized loss	(20,546,000)
Total, unrealized loss	(20,687,000)
Debt Securities, Available-for-Sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Available-for-sale asset-backed securities, unrealized loss position less than 12 months, fair value	57,234,000
Available-for-sale asset-backed securities, unrealized loss position 12 months or more, fair value	312,777,000
Total, fair value	370,011,000
Asset-Backed Securities, Available-For-Sale, Federal Family Education Loan Program (FFELP) Loans, Restricted Investments
Debt Securities, Available-for-Sale, Unrealized Loss Position [Abstract]
Available-for-sale asset-backed securities, unrealized loss position less than 12 months, unrealized loss	(24,000)
Available-for-sale asset-backed securities, unrealized loss position 12 months or more, unrealized loss	(54,000)
Total, unrealized loss	(78,000)
Debt Securities, Available-for-Sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Available-for-sale asset-backed securities, unrealized loss position less than 12 months, fair value	7,843,000
Available-for-sale asset-backed securities, unrealized loss position 12 months or more, fair value	2,463,000
Total, fair value	10,306,000
Asset-Backed Securities, Available-For-Sale, Non-Nelnet Bank
Debt Securities, Available-for-Sale, Unrealized Loss Position [Abstract]
Available-for-sale asset-backed securities, unrealized loss position less than 12 months, unrealized loss	(26,000)
Available-for-sale asset-backed securities, unrealized loss position 12 months or more, unrealized loss	(19,066,000)
Total, unrealized loss	(19,092,000)
Debt Securities, Available-for-Sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Available-for-sale asset-backed securities, unrealized loss position less than 12 months, fair value	11,908,000
Available-for-sale asset-backed securities, unrealized loss position 12 months or more, fair value	282,133,000
Total, fair value	294,041,000
Asset-Backed Securities, Available-For-Sale, Federal Family Education Loan Program (FFELP) Loans, Non-Nelnet Bank
Debt Securities, Available-for-Sale, Unrealized Loss Position [Abstract]
Available-for-sale asset-backed securities, unrealized loss position less than 12 months, unrealized loss	(2,000)
Available-for-sale asset-backed securities, unrealized loss position 12 months or more, unrealized loss	(894,000)
Total, unrealized loss	(896,000)
Debt Securities, Available-for-Sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Available-for-sale asset-backed securities, unrealized loss position less than 12 months, fair value	4,065,000
Available-for-sale asset-backed securities, unrealized loss position 12 months or more, fair value	60,500,000
Total, fair value	64,565,000
Asset-Backed Securities, Available-For-Sale, Private Education Loans, Non-Nelnet Bank
Debt Securities, Available-for-Sale, Unrealized Loss Position [Abstract]
Available-for-sale asset-backed securities, unrealized loss position less than 12 months, unrealized loss	0
Available-for-sale asset-backed securities, unrealized loss position 12 months or more, unrealized loss	(18,118,000)
Total, unrealized loss	(18,118,000)
Debt Securities, Available-for-Sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Available-for-sale asset-backed securities, unrealized loss position less than 12 months, fair value	0
Available-for-sale asset-backed securities, unrealized loss position 12 months or more, fair value	219,170,000
Total, fair value	219,170,000
Asset-Backed Securities, Available-For-Sale, Nelnet Bank
Debt Securities, Available-for-Sale, Unrealized Loss Position [Abstract]
Available-for-sale asset-backed securities, unrealized loss position less than 12 months, unrealized loss	(115,000)
Available-for-sale asset-backed securities, unrealized loss position 12 months or more, unrealized loss	(1,480,000)
Total, unrealized loss	(1,595,000)
Debt Securities, Available-for-Sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Available-for-sale asset-backed securities, unrealized loss position less than 12 months, fair value	45,326,000
Available-for-sale asset-backed securities, unrealized loss position 12 months or more, fair value	30,644,000
Total, fair value	75,970,000
Asset-Backed Securities, Available-For-Sale, Federal Family Education Loan Program (FFELP) Loans, Nelnet Bank
Debt Securities, Available-for-Sale, Unrealized Loss Position [Abstract]
Available-for-sale asset-backed securities, unrealized loss position less than 12 months, unrealized loss	(69,000)
Available-for-sale asset-backed securities, unrealized loss position 12 months or more, unrealized loss	(201,000)
Total, unrealized loss	(270,000)
Debt Securities, Available-for-Sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Available-for-sale asset-backed securities, unrealized loss position less than 12 months, fair value	30,297,000
Available-for-sale asset-backed securities, unrealized loss position 12 months or more, fair value	16,586,000
Total, fair value	46,883,000
Asset-Backed Securities, Available-For-Sale, Other, Nelnet Bank
Debt Securities, Available-for-Sale, Unrealized Loss Position [Abstract]
Available-for-sale asset-backed securities, unrealized loss position less than 12 months, unrealized loss	(46,000)
Available-for-sale asset-backed securities, unrealized loss position 12 months or more, unrealized loss	(1,279,000)
Total, unrealized loss	(1,325,000)
Debt Securities, Available-for-Sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Available-for-sale asset-backed securities, unrealized loss position less than 12 months, fair value	15,029,000
Available-for-sale asset-backed securities, unrealized loss position 12 months or more, fair value	14,058,000
Total, fair value	$ 29,087,000

X

- Definition

Debt Securities, Available-for-sale, Unrealized Loss Position, Due to Credit Loss

+ References

No definition available.

+ Details

Name:	nni_DebtSecuritiesAvailableForSaleUnrealizedLossPositionDueToCreditLoss
Namespace Prefix:	nni_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- References

No definition available.

+ Details

Name:	us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLossAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 55
-Paragraph 8
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479081/326-30-55-8

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479106/326-30-50-4

+ Details

Name:	us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValueAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 55
-Paragraph 8
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479081/326-30-55-8

Reference 2: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 7
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481800/320-10-50-7

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479106/326-30-50-5

+ Details

Name:	us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for 12 months or longer, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 7
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481800/320-10-50-7

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479106/326-30-50-5

+ Details

Name:	us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for less than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 55
-Paragraph 8
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479081/326-30-55-8

Reference 2: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 7
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481800/320-10-50-7

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479106/326-30-50-5

+ Details

Name:	us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for less than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 7
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481800/320-10-50-7

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479106/326-30-50-5

+ Details

Name:	us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in unrealized loss position without allowance for credit loss.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 55
-Paragraph 8
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479081/326-30-55-8

Reference 2: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Subparagraph (a)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481800/320-10-50-6

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (a)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479106/326-30-50-4

+ Details

Name:	us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in unrealized loss position, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Subparagraph (a)(2)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481800/320-10-50-6

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (a)(2)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479106/326-30-50-4

+ Details

Name:	us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- References

No definition available.

+ Details

Name:	us-gaap_DebtSecuritiesAvailableforSaleUnrealizedLossPositionAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Details

Name:	us-gaap_FinancialInstrumentAxis=nni_AssetBackedSecuritiesAvailableForSaleFederalFamilyEducationLoanProgramFFELPLoansRestrictedInvestmentsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancialInstrumentAxis=nni_AssetBackedSecuritiesAvailableForSaleNonNelnetBankMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancialInstrumentAxis=nni_AssetBackedSecuritiesAvailableForSaleFederalFamilyEducationLoanProgramFFELPLoansNonNelnetBankMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancialInstrumentAxis=nni_AssetBackedSecuritiesAvailableForSalePrivateEducationLoansNonNelnetBankMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancialInstrumentAxis=nni_AssetBackedSecuritiesAvailableForSaleNelnetBankMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancialInstrumentAxis=nni_AssetBackedSecuritiesAvailableForSaleFederalFamilyEducationLoanProgramFFELPLoansNelnetBankMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancialInstrumentAxis=nni_AssetBackedSecuritiesAvailableForSaleOtherNelnetBankMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: