composition of loans receivable and the allowance for loan losses (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Totals	$ 1,041,185	$ 1,027,738
Allowance For Loan And Lease Losses Collectively Evaluated Loans [Member]
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Residential 1-4 family	340,398	347,695
Residential 5+ multifamily	36,826	36,094
Construction of residential 1-4 family	10,435	8,814
Home equity lines of credit	26,003	27,650
Residential real estate	413,662	420,253
Commercial	301,526	305,193
Construction of commercial	34,312	31,722
Commercial real estate	335,838	336,915
Farm land	3,455	3,040
Vacant land	13,064	13,912
Real estate secured	766,019	774,120
Commercial and industrial	248,925	226,662
Municipal	21,495	21,512
Consumer	8,593	7,661
Unallocated allowance
Totals	1,045,032	1,029,955
SEC Schedule, 12-09, Allowance, Loan and Lease Loss, Real Estate [Member]
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Residential 1-4 family	2,337	2,445
Residential 5+ multifamily	622	686
Construction of residential 1-4 family	77	65
Home equity lines of credit	195	232
Residential real estate	3,231	3,428
Commercial	6,946	6,298
Construction of commercial	584	596
Commercial real estate	7,530	6,894
Farm land	50	59
Vacant land	107	178
Real estate secured	10,918	10,559
Commercial and industrial	1,247	1,223
Municipal	43	43
Consumer	52	59
Unallocated allowance	1,275	1,207
Totals	13,535	13,091
Allowance For Loan And Lease Losses Individually Evaluated Loans [Member]
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Residential 1-4 family	4,129	4,306
Residential 5+ multifamily	963	964
Construction of residential 1-4 family
Home equity lines of credit	237	154
Residential real estate	5,329	5,424
Commercial	5,304	5,648
Construction of commercial
Commercial real estate	5,304	5,648
Farm land	151	158
Vacant land	164	167
Real estate secured	10,948	11,397
Commercial and industrial	432	486
Municipal
Consumer	24	26
Unallocated allowance
Totals	11,404	11,909
SEC Schedule, 12-09, Allowance, Loan and Lease Loss [Member]
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Residential 1-4 family	93	201
Residential 5+ multifamily
Construction of residential 1-4 family
Home equity lines of credit		20
Residential real estate	93	221
Commercial	134	248
Construction of commercial
Commercial real estate	134	248
Farm land
Vacant land	2	2
Real estate secured	229	471
Commercial and industrial	122	174
Municipal
Consumer		18
Unallocated allowance
Totals	351	663
Allowance For Loan And Lease Losses Total Portfolio Loans [Member]
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Residential 1-4 family	344,527	352,001
Residential 5+ multifamily	37,789	37,058
Construction of residential 1-4 family	10,435	8,814
Home equity lines of credit	26,240	27,804
Residential real estate	418,991	425,677
Commercial	306,830	310,841
Construction of commercial	34,312	31,722
Commercial real estate	341,142	342,563
Farm land	3,606	3,198
Vacant land	13,228	14,079
Real estate secured	776,967	785,517
Commercial and industrial	249,357	227,148
Municipal	21,495	21,512
Consumer	8,617	7,687
Unallocated allowance
Totals	1,056,436	1,041,864
Allowance For Loan And Lease Losses Total Portfolio Allowance [Member]
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Residential 1-4 family	2,430	2,646
Residential 5+ multifamily	622	686
Construction of residential 1-4 family	77	65
Home equity lines of credit	195	252
Residential real estate	3,324	3,649
Commercial	7,080	6,546
Construction of commercial	584	596
Commercial real estate	7,664	7,142
Farm land	50	59
Vacant land	109	180
Real estate secured	11,147	11,030
Commercial and industrial	1,369	1,397
Municipal	43	43
Consumer	52	77
Unallocated allowance	1,275	1,207
Totals	$ 13,886	$ 13,754

No definition available.

Name:	SAL_InventoryRealEstateCommercial
Namespace Prefix:	SAL_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

+ Details

Name:	SAL_InventoryRealEstateCommercialAndIndustrial
Namespace Prefix:	SAL_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

+ Details

Name:	SAL_InventoryRealEstateCommercialRealEstate
Namespace Prefix:	SAL_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

+ Details

Name:	SAL_InventoryRealEstateFarmLand
Namespace Prefix:	SAL_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

+ Details

Name:	SAL_InventoryRealEstateMultifamily
Namespace Prefix:	SAL_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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:	srt_ValuationAndQualifyingAccountsDisclosureLineItems
Namespace Prefix:	srt_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

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

+ References

No definition available.

+ Details

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

- Definition

The fair value as of the balance sheet date of firm holdings in fixed income obligations issued by state and local governments and authorities. Includes both pledged (to counterparties as collateral for financing transactions) and unpledged holdings.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 940
-SubTopic 320
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=35711157&loc=d3e42546-110969

+ Details

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

- Definition

The net carrying amount as of the balance sheet date of the sum of the various components of an operative builder's inventory, including finished homes. Operative builders primarily consist of entities that develop land, construct residential homes and commercial and industrial buildings thereon, and sell them to home buyers and operators of the commercial and industrial properties.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.6(a))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

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

- Definition

Total of (1) improvements, (2) held-for-sale, (3) land and land under development, (4) construction-in-process, (5) mortgage loans held-in-inventory, and (6) other real estate investments which are considered inventory due to being held for sale or disposition.

+ References

No definition available.

+ Details

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

- Definition

Cost of real estate projects incurred for projects for eventual sale or transfer (condominium or time share projects, vacation clubs).

+ References

No definition available.

+ Details

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

- Definition

Carrying amount as of the balance sheet date, net of valuation allowances and impairment losses, of costs of land expected to be developed in the near term plus capitalized costs of development, for purposes of selling completed units to home buyers or commercial or industrial entities..

+ References

+ Details

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

- Definition

Represents mortgage loans held in inventory primarily for sale to others (third parties, businesses, legal entities) in the ordinary course of business.

+ References

No definition available.

+ Details

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

- Definition

Amount of investment in certain other real estate investments not specifically identified elsewhere in the existing taxonomy.

+ References

No definition available.

+ Details

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

- Definition

Amount before allowance and after 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.

+ 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 310
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=123577603&loc=d3e5074-111524

+ Details

Name:	us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
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

The balance represents the amount of loans that are secured by real estate mortgages, offset by the reserve to cover probable credit losses on the loan portfolio.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.1(c))
-URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910

+ Details

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

- Details

Name:	us-gaap_ValuationAllowancesAndReservesTypeAxis=SAL_AllowanceForLoanAndLeaseLossesCollectivelyEvaluatedLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ValuationAllowancesAndReservesTypeAxis=us-gaap_AllowanceForLoanAndLeaseLossesRealEstateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ValuationAllowancesAndReservesTypeAxis=SAL_AllowanceForLoanAndLeaseLossesIndividuallyEvaluatedLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ValuationAllowancesAndReservesTypeAxis=us-gaap_AllowanceForLoanAndLeaseLossesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ValuationAllowancesAndReservesTypeAxis=SAL_AllowanceForLoanAndLeaseLossesTotalPortfolioLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ValuationAllowancesAndReservesTypeAxis=SAL_AllowanceForLoanAndLeaseLossesTotalPortfolioAllowanceMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: