credit quality segments of loans receivable and the allowance for loan losses (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Financing Receivable, Past Due [Line Items]
Totals	$ 1,057,451	$ 1,027,738
Allowance For Loan And Lease Losses Collectively Evaluated Loans Credit Quality Segment [Member]
Financing Receivable, Past Due [Line Items]
Performing loans	1,025,195	1,011,757
Potential problem loans 1	36,795	18,198
Impaired loans
Unallocated allowance
Totals	1,061,990	1,029,955
Allowance For Loan And Lease Losses Collectively Evaluated Allowance Credit Quality Segment [Member]
Financing Receivable, Past Due [Line Items]
Performing loans	9,490	10,424
Potential problem loans 1	2,741	1,460
Impaired loans
Unallocated allowance	847	1,207
Totals	13,078	13,091
Allowance For Loan And Lease Losses Individually Evaluated Loans Credit Quality Segment [Member]
Financing Receivable, Past Due [Line Items]
Performing loans
Potential problem loans 1
Impaired loans	8,943	11,909
Unallocated allowance
Totals	8,943	11,909
Allowance For Loan And Lease Losses Individually Evaluated Allowance Credit Quality Segment [Member]
Financing Receivable, Past Due [Line Items]
Performing loans
Potential problem loans 1
Impaired loans	90	663
Unallocated allowance
Totals	90	663
Allowance For Loan And Lease Losses Total Portfolio Loans Credit Quality Segment [Member]
Financing Receivable, Past Due [Line Items]
Performing loans	1,025,195	1,011,757
Potential problem loans 1	36,795	18,198
Impaired loans	8,943	11,909
Unallocated allowance
Totals	1,070,933	1,041,864
Allowance For Loan And Lease Losses Total Portfolio Allowance Credit Quality Segment [Member]
Financing Receivable, Past Due [Line Items]
Performing loans	9,490	10,424
Potential problem loans 1	2,741	1,460
Impaired loans	90	663
Unallocated allowance	847	1,207
Totals	$ 13,168	$ 13,754

Amount of allowance for credit loss on receivable, classified as other and current.

No definition available.

Name:	us-gaap_AllowanceForDoubtfulOtherReceivablesCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- 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

No definition available.

+ Details

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

- Definition

Reflects the carrying amount of loans deemed to be questionable as to collection on which interest is continuing to be earned or accrued.

+ References

No definition available.

+ Details

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

- Definition

Reflects the carrying amount of loans deemed to be questionable as to collection on which no interest is continuing to be recognized.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 7
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123577603&loc=d3e5111-111524

+ Details

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

- Definition

Amount after allowance and deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements and loans held for sale.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=124259787&loc=d3e4428-111522

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.7)
-URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878

+ Details

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

- Definition

Amount of loan with fixed rate of interest.

+ References

+ Details

Name:	us-gaap_LoansReceivableWithFixedRatesOfInterest1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=SAL_AllowanceForLoanAndLeaseLossesCollectivelyEvaluatedLoansCreditQualitySegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=SAL_AllowanceForLoanAndLeaseLossesCollectivelyEvaluatedAllowanceCreditQualitySegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=SAL_AllowanceForLoanAndLeaseLossesIndividuallyEvaluatedLoansCreditQualitySegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=SAL_AllowanceForLoanAndLeaseLossesIndividuallyEvaluatedAllowanceCreditQualitySegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=SAL_AllowanceForLoanAndLeaseLossesTotalPortfolioLoansCreditQualitySegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=SAL_AllowanceForLoanAndLeaseLossesTotalPortfolioAllowanceCreditQualitySegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: