XML 36 R36.htm IDEA: XBRL DOCUMENT v2.4.1.9
Loans Receivable - Credit Quality Indicators by Class of Loan (Details) (USD $)
In Thousands, unless otherwise specified
Mar. 31, 2015
Jun. 30, 2014
Financing Receivable, Recorded Investment [Line Items]    
Loans $ 499,265us-gaap_LoansAndLeasesReceivableGrossCarryingAmount $ 503,828us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
Pass    
Financing Receivable, Recorded Investment [Line Items]    
Loans 449,893us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember		 458,624us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember
Watch    
Financing Receivable, Recorded Investment [Line Items]    
Loans 33,050us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_InternalCreditAssessmentAxis
= fnwb_WatchMember		 26,027us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_InternalCreditAssessmentAxis
= fnwb_WatchMember
Special Mention    
Financing Receivable, Recorded Investment [Line Items]    
Loans 6,359us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember		 5,234us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember
Sub-standard    
Financing Receivable, Recorded Investment [Line Items]    
Loans 9,963us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SubstandardMember		 13,943us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SubstandardMember
Nonperforming    
Financing Receivable, Recorded Investment [Line Items]    
Loans 4,494us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_NonperformingFinancingReceivableMember		 5,964us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_NonperformingFinancingReceivableMember
Performing    
Financing Receivable, Recorded Investment [Line Items]    
Loans 494,771us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		 497,864us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember
One to four family    
Financing Receivable, Recorded Investment [Line Items]    
Loans 259,926us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
= us-gaap_ResidentialPortfolioSegmentMember		 241,910us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
= us-gaap_ResidentialPortfolioSegmentMember
One to four family | Olympic Peninsula | Real estate loans    
Financing Receivable, Recorded Investment [Line Items]    
Loans 169,423us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
= us-gaap_ResidentialPortfolioSegmentMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fnwb_RealEstateLoanMember
/ us-gaap_StatementGeographicalAxis
= fnwb_OlympicPeninsulaMember		 167,910us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
= us-gaap_ResidentialPortfolioSegmentMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fnwb_RealEstateLoanMember
/ us-gaap_StatementGeographicalAxis
= fnwb_OlympicPeninsulaMember
One to four family | Olympic Peninsula | Real estate loans | Pass    
Financing Receivable, Recorded Investment [Line Items]    
Loans 161,234us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
= us-gaap_ResidentialPortfolioSegmentMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fnwb_RealEstateLoanMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember
/ us-gaap_StatementGeographicalAxis
= fnwb_OlympicPeninsulaMember		 156,484us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
= us-gaap_ResidentialPortfolioSegmentMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fnwb_RealEstateLoanMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember
/ us-gaap_StatementGeographicalAxis
= fnwb_OlympicPeninsulaMember
One to four family | Olympic Peninsula | Real estate loans | Watch    
Financing Receivable, Recorded Investment [Line Items]    
Loans 3,360us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
= us-gaap_ResidentialPortfolioSegmentMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fnwb_RealEstateLoanMember
/ us-gaap_InternalCreditAssessmentAxis
= fnwb_WatchMember
/ us-gaap_StatementGeographicalAxis
= fnwb_OlympicPeninsulaMember		 4,154us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
= us-gaap_ResidentialPortfolioSegmentMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fnwb_RealEstateLoanMember
/ us-gaap_InternalCreditAssessmentAxis
= fnwb_WatchMember
/ us-gaap_StatementGeographicalAxis
= fnwb_OlympicPeninsulaMember
One to four family | Olympic Peninsula | Real estate loans | Special Mention    
Financing Receivable, Recorded Investment [Line Items]    
Loans 1,013us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
= us-gaap_ResidentialPortfolioSegmentMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fnwb_RealEstateLoanMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember
/ us-gaap_StatementGeographicalAxis
= fnwb_OlympicPeninsulaMember		 2,114us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
= us-gaap_ResidentialPortfolioSegmentMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fnwb_RealEstateLoanMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember
/ us-gaap_StatementGeographicalAxis
= fnwb_OlympicPeninsulaMember
One to four family | Olympic Peninsula | Real estate loans | Sub-standard    
Financing Receivable, Recorded Investment [Line Items]    
Loans 3,816us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
= us-gaap_ResidentialPortfolioSegmentMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fnwb_RealEstateLoanMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SubstandardMember
/ us-gaap_StatementGeographicalAxis
= fnwb_OlympicPeninsulaMember		 5,158us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
= us-gaap_ResidentialPortfolioSegmentMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fnwb_RealEstateLoanMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SubstandardMember
/ us-gaap_StatementGeographicalAxis
= fnwb_OlympicPeninsulaMember
One to four family | Olympic Peninsula | Real estate loans | Nonperforming    
Financing Receivable, Recorded Investment [Line Items]    
Loans 3,142us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
= us-gaap_ResidentialPortfolioSegmentMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fnwb_RealEstateLoanMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_NonperformingFinancingReceivableMember
/ us-gaap_StatementGeographicalAxis
= fnwb_OlympicPeninsulaMember		 3,223us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
= us-gaap_ResidentialPortfolioSegmentMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fnwb_RealEstateLoanMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_NonperformingFinancingReceivableMember
/ us-gaap_StatementGeographicalAxis
= fnwb_OlympicPeninsulaMember
One to four family | Olympic Peninsula | Real estate loans | Performing    
Financing Receivable, Recorded Investment [Line Items]    
Loans 166,281us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
= us-gaap_ResidentialPortfolioSegmentMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fnwb_RealEstateLoanMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember
/ us-gaap_StatementGeographicalAxis
= fnwb_OlympicPeninsulaMember		 164,687us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
= us-gaap_ResidentialPortfolioSegmentMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fnwb_RealEstateLoanMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember
/ us-gaap_StatementGeographicalAxis
= fnwb_OlympicPeninsulaMember
One to four family | Other locations | Real estate loans    
Financing Receivable, Recorded Investment [Line Items]    
Loans 90,503us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
= us-gaap_ResidentialPortfolioSegmentMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fnwb_RealEstateLoanMember
/ us-gaap_StatementGeographicalAxis
= fnwb_OtherLocationsMember		 74,000us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
= us-gaap_ResidentialPortfolioSegmentMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fnwb_RealEstateLoanMember
/ us-gaap_StatementGeographicalAxis
= fnwb_OtherLocationsMember
One to four family | Other locations | Real estate loans | Pass    
Financing Receivable, Recorded Investment [Line Items]    
Loans 88,238us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
= us-gaap_ResidentialPortfolioSegmentMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fnwb_RealEstateLoanMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember
/ us-gaap_StatementGeographicalAxis
= fnwb_OtherLocationsMember		 72,809us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
= us-gaap_ResidentialPortfolioSegmentMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fnwb_RealEstateLoanMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember
/ us-gaap_StatementGeographicalAxis
= fnwb_OtherLocationsMember
One to four family | Other locations | Real estate loans | Watch    
Financing Receivable, Recorded Investment [Line Items]    
Loans 1,290us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
= us-gaap_ResidentialPortfolioSegmentMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fnwb_RealEstateLoanMember
/ us-gaap_InternalCreditAssessmentAxis
= fnwb_WatchMember
/ us-gaap_StatementGeographicalAxis
= fnwb_OtherLocationsMember		 203us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
= us-gaap_ResidentialPortfolioSegmentMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fnwb_RealEstateLoanMember
/ us-gaap_InternalCreditAssessmentAxis
= fnwb_WatchMember
/ us-gaap_StatementGeographicalAxis
= fnwb_OtherLocationsMember
One to four family | Other locations | Real estate loans | Special Mention    
Financing Receivable, Recorded Investment [Line Items]    
Loans 0us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
= us-gaap_ResidentialPortfolioSegmentMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fnwb_RealEstateLoanMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember
/ us-gaap_StatementGeographicalAxis
= fnwb_OtherLocationsMember		 605us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
= us-gaap_ResidentialPortfolioSegmentMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fnwb_RealEstateLoanMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember
/ us-gaap_StatementGeographicalAxis
= fnwb_OtherLocationsMember
One to four family | Other locations | Real estate loans | Sub-standard    
Financing Receivable, Recorded Investment [Line Items]    
Loans 975us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
= us-gaap_ResidentialPortfolioSegmentMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fnwb_RealEstateLoanMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SubstandardMember
/ us-gaap_StatementGeographicalAxis
= fnwb_OtherLocationsMember		 383us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
= us-gaap_ResidentialPortfolioSegmentMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fnwb_RealEstateLoanMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SubstandardMember
/ us-gaap_StatementGeographicalAxis
= fnwb_OtherLocationsMember
One to four family | Other locations | Real estate loans | Nonperforming    
Financing Receivable, Recorded Investment [Line Items]    
Loans 415us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
= us-gaap_ResidentialPortfolioSegmentMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fnwb_RealEstateLoanMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_NonperformingFinancingReceivableMember
/ us-gaap_StatementGeographicalAxis
= fnwb_OtherLocationsMember		 320us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
= us-gaap_ResidentialPortfolioSegmentMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fnwb_RealEstateLoanMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_NonperformingFinancingReceivableMember
/ us-gaap_StatementGeographicalAxis
= fnwb_OtherLocationsMember
One to four family | Other locations | Real estate loans | Performing    
Financing Receivable, Recorded Investment [Line Items]    
Loans 90,088us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
= us-gaap_ResidentialPortfolioSegmentMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fnwb_RealEstateLoanMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember
/ us-gaap_StatementGeographicalAxis
= fnwb_OtherLocationsMember		 73,680us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
= us-gaap_ResidentialPortfolioSegmentMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fnwb_RealEstateLoanMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember
/ us-gaap_StatementGeographicalAxis
= fnwb_OtherLocationsMember
Commercial    
Financing Receivable, Recorded Investment [Line Items]    
Loans 179,901us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember		 190,660us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
Commercial | Real estate loans    
Financing Receivable, Recorded Investment [Line Items]    
Loans 128,249us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fnwb_RealEstateLoanMember		 128,028us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fnwb_RealEstateLoanMember
Commercial | Real estate loans | Pass    
Financing Receivable, Recorded Investment [Line Items]    
Loans 109,871us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fnwb_RealEstateLoanMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember		 111,319us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fnwb_RealEstateLoanMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember
Commercial | Real estate loans | Watch    
Financing Receivable, Recorded Investment [Line Items]    
Loans 10,571us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fnwb_RealEstateLoanMember
/ us-gaap_InternalCreditAssessmentAxis
= fnwb_WatchMember		 9,471us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fnwb_RealEstateLoanMember
/ us-gaap_InternalCreditAssessmentAxis
= fnwb_WatchMember
Commercial | Real estate loans | Special Mention    
Financing Receivable, Recorded Investment [Line Items]    
Loans 4,948us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fnwb_RealEstateLoanMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember		 1,570us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fnwb_RealEstateLoanMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember
Commercial | Real estate loans | Sub-standard    
Financing Receivable, Recorded Investment [Line Items]    
Loans 2,859us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fnwb_RealEstateLoanMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SubstandardMember		 5,668us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fnwb_RealEstateLoanMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SubstandardMember
Commercial | Real estate loans | Nonperforming    
Financing Receivable, Recorded Investment [Line Items]    
Loans 204us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fnwb_RealEstateLoanMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_NonperformingFinancingReceivableMember		 1,913us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fnwb_RealEstateLoanMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_NonperformingFinancingReceivableMember
Commercial | Real estate loans | Performing    
Financing Receivable, Recorded Investment [Line Items]    
Loans 128,045us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fnwb_RealEstateLoanMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember		 126,115us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fnwb_RealEstateLoanMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PerformingFinancingReceivableMember
Commercial | Multi-family    
Financing Receivable, Recorded Investment [Line Items]    
Loans 37,044us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fnwb_MultifamilyLoansMember		 45,100us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fnwb_MultifamilyLoansMember
Commercial | Multi-family | Pass    
Financing Receivable, Recorded Investment [Line Items]    
Loans 25,953us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fnwb_MultifamilyLoansMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember		 39,879us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fnwb_MultifamilyLoansMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember
Commercial | Multi-family | Watch    
Financing Receivable, Recorded Investment [Line Items]    
Loans 10,458us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fnwb_MultifamilyLoansMember
/ us-gaap_InternalCreditAssessmentAxis
= fnwb_WatchMember		 4,337us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fnwb_MultifamilyLoansMember
/ us-gaap_InternalCreditAssessmentAxis
= fnwb_WatchMember
Commercial | Multi-family | Special Mention    
Financing Receivable, Recorded Investment [Line Items]    
Loans 0us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fnwb_MultifamilyLoansMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember		 0us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fnwb_MultifamilyLoansMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember
Commercial | Multi-family | Sub-standard    
Financing Receivable, Recorded Investment [Line Items]    
Loans 633us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
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Commercial | Multi-family | Nonperforming    
Financing Receivable, Recorded Investment [Line Items]    
Loans 0us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
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Commercial | Multi-family | Performing    
Financing Receivable, Recorded Investment [Line Items]    
Loans 37,044us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
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Commercial | Business    
Financing Receivable, Recorded Investment [Line Items]    
Loans 14,608us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
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Commercial | Business | Pass    
Financing Receivable, Recorded Investment [Line Items]    
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Commercial | Business | Watch    
Financing Receivable, Recorded Investment [Line Items]    
Loans 6,051us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
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Commercial | Business | Special Mention    
Financing Receivable, Recorded Investment [Line Items]    
Loans 94us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
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Commercial | Business | Sub-standard    
Financing Receivable, Recorded Investment [Line Items]    
Loans 631us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
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Commercial | Business | Nonperforming    
Financing Receivable, Recorded Investment [Line Items]    
Loans 181us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
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Commercial | Business | Performing    
Financing Receivable, Recorded Investment [Line Items]    
Loans 14,427us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
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Consumer    
Financing Receivable, Recorded Investment [Line Items]    
Loans 45,507us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
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Consumer | Home equity    
Financing Receivable, Recorded Investment [Line Items]    
Loans 36,905us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
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Consumer | Home equity | Pass    
Financing Receivable, Recorded Investment [Line Items]    
Loans 35,533us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
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Consumer | Home equity | Watch    
Financing Receivable, Recorded Investment [Line Items]    
Loans 676us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
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Consumer | Home equity | Special Mention    
Financing Receivable, Recorded Investment [Line Items]    
Loans 204us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
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Consumer | Home equity | Sub-standard    
Financing Receivable, Recorded Investment [Line Items]    
Loans 492us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
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Consumer | Home equity | Nonperforming    
Financing Receivable, Recorded Investment [Line Items]    
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Consumer | Home equity | Performing    
Financing Receivable, Recorded Investment [Line Items]    
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Consumer | Auto    
Financing Receivable, Recorded Investment [Line Items]    
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Consumer | Auto | Pass    
Financing Receivable, Recorded Investment [Line Items]    
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Consumer | Auto | Watch    
Financing Receivable, Recorded Investment [Line Items]    
Loans 97us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
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Consumer | Auto | Special Mention    
Financing Receivable, Recorded Investment [Line Items]    
Loans 51us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
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Consumer | Auto | Sub-standard    
Financing Receivable, Recorded Investment [Line Items]    
Loans 21us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
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Consumer | Auto | Nonperforming    
Financing Receivable, Recorded Investment [Line Items]    
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Consumer | Auto | Performing    
Financing Receivable, Recorded Investment [Line Items]    
Loans 4,251us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
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Consumer | Consumer other    
Financing Receivable, Recorded Investment [Line Items]    
Loans 4,351us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
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Consumer | Consumer other | Pass    
Financing Receivable, Recorded Investment [Line Items]    
Loans 3,994us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
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Consumer | Consumer other | Watch    
Financing Receivable, Recorded Investment [Line Items]    
Loans 128us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
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Consumer | Consumer other | Special Mention    
Financing Receivable, Recorded Investment [Line Items]    
Loans 1us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
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Consumer | Consumer other | Sub-standard    
Financing Receivable, Recorded Investment [Line Items]    
Loans 228us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
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/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
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Consumer | Consumer other | Nonperforming    
Financing Receivable, Recorded Investment [Line Items]    
Loans 99us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
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Consumer | Consumer other | Performing    
Financing Receivable, Recorded Investment [Line Items]    
Loans 4,252us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
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Construction and land    
Financing Receivable, Recorded Investment [Line Items]    
Loans 13,931us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
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Construction and land | Construction    
Financing Receivable, Recorded Investment [Line Items]    
Loans 3,034us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
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/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
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Construction and land | Construction | Pass    
Financing Receivable, Recorded Investment [Line Items]    
Loans 3,034us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
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Construction and land | Construction | Watch    
Financing Receivable, Recorded Investment [Line Items]    
Loans 0us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
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Construction and land | Construction | Special Mention    
Financing Receivable, Recorded Investment [Line Items]    
Loans 0us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
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/ us-gaap_InternalCreditAssessmentAxis
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/ fnwb_FinancingReceivablePortfolioSegmentAxis
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/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
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/ us-gaap_InternalCreditAssessmentAxis
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Construction and land | Construction | Sub-standard    
Financing Receivable, Recorded Investment [Line Items]    
Loans 0us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
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/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
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/ us-gaap_InternalCreditAssessmentAxis
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/ fnwb_FinancingReceivablePortfolioSegmentAxis
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/ us-gaap_InternalCreditAssessmentAxis
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Construction and land | Construction | Nonperforming    
Financing Receivable, Recorded Investment [Line Items]    
Loans 0us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
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/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
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/ us-gaap_InternalCreditAssessmentAxis
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/ fnwb_FinancingReceivablePortfolioSegmentAxis
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/ us-gaap_InternalCreditAssessmentAxis
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Construction and land | Construction | Performing    
Financing Receivable, Recorded Investment [Line Items]    
Loans 3,034us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
= fnwb_ConstructionandLandPortfolioSegmentMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
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/ us-gaap_InternalCreditAssessmentAxis
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/ fnwb_FinancingReceivablePortfolioSegmentAxis
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/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
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/ us-gaap_InternalCreditAssessmentAxis
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Construction and land | Land and development    
Financing Receivable, Recorded Investment [Line Items]    
Loans 10,897us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
= fnwb_ConstructionandLandPortfolioSegmentMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
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/ fnwb_FinancingReceivablePortfolioSegmentAxis
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/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
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Construction and land | Land and development | Pass    
Financing Receivable, Recorded Investment [Line Items]    
Loans 10,122us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
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/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
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/ us-gaap_InternalCreditAssessmentAxis
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/ fnwb_FinancingReceivablePortfolioSegmentAxis
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/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fnwb_LandandDevelopmentLoansMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember
Construction and land | Land and development | Watch    
Financing Receivable, Recorded Investment [Line Items]    
Loans 419us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
= fnwb_ConstructionandLandPortfolioSegmentMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fnwb_LandandDevelopmentLoansMember
/ us-gaap_InternalCreditAssessmentAxis
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/ fnwb_FinancingReceivablePortfolioSegmentAxis
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/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
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/ us-gaap_InternalCreditAssessmentAxis
= fnwb_WatchMember
Construction and land | Land and development | Special Mention    
Financing Receivable, Recorded Investment [Line Items]    
Loans 48us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
= fnwb_ConstructionandLandPortfolioSegmentMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fnwb_LandandDevelopmentLoansMember
/ us-gaap_InternalCreditAssessmentAxis
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/ fnwb_FinancingReceivablePortfolioSegmentAxis
= fnwb_ConstructionandLandPortfolioSegmentMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fnwb_LandandDevelopmentLoansMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember
Construction and land | Land and development | Sub-standard    
Financing Receivable, Recorded Investment [Line Items]    
Loans 308us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
= fnwb_ConstructionandLandPortfolioSegmentMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
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/ us-gaap_InternalCreditAssessmentAxis
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/ fnwb_FinancingReceivablePortfolioSegmentAxis
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/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
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/ us-gaap_InternalCreditAssessmentAxis
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Construction and land | Land and development | Nonperforming    
Financing Receivable, Recorded Investment [Line Items]    
Loans 231us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
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/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
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/ us-gaap_InternalCreditAssessmentAxis
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/ fnwb_FinancingReceivablePortfolioSegmentAxis
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/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
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/ us-gaap_InternalCreditAssessmentAxis
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Construction and land | Land and development | Performing    
Financing Receivable, Recorded Investment [Line Items]    
Loans $ 10,666us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ fnwb_FinancingReceivablePortfolioSegmentAxis
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/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= fnwb_LandandDevelopmentLoansMember
/ us-gaap_InternalCreditAssessmentAxis
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/ fnwb_FinancingReceivablePortfolioSegmentAxis
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/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
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