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Organization and Business - Additional Information (Detail)	0 Months Ended	12 Months Ended
	May 29, 2013 Entity	Dec. 31, 2013 Entity
Organization Consolidation And Presentation Of Financial Statements [Abstract]
FFELP loan portfolio amortization period		20 years
Number of separate publicly traded entities	2	2

X

- Definition

A description of the remaining amortization period of the company's FFELP loan portfolio.

+ References

No definition available.

+ Details

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Data Type:	xbrli:durationItemType
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X

- Definition

Number of divisions of existing businesses under separation transaction.

+ References

No definition available.

+ Details

Name:	navi_NumberOfDivisionsOfExistingBusinessesUnderSeparationTransaction
Namespace Prefix:	navi_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

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- Details

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