Amount before allowance of loans and deferred loan origination fees.

No definition available.

Name:	slct_LoansAndLeasesReceivableGrossCarryingAmountBeforeDeferredLoanOriginationFees
Namespace Prefix:	slct_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The percentage of deferred origination fees.

+ References

No definition available.

+ Details

Name:	slct_PercentageOfDeferredOriginationFees
Namespace Prefix:	slct_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The percentage of loan and lease receivables .

+ References

No definition available.

+ Details

Name:	slct_PercentageOfLoansAndLeasesReceivableGrossCarryingAmount
Namespace Prefix:	slct_
Data Type:	num:percentItemType
Balance Type:	na
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_AccountsNotesAndLoansReceivableLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

+ 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 210.5-02.17)
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=119993939&loc=d3e28555-108399

+ Details

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

- Definition

Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for 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 50
-Paragraph 11B
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=121611835&loc=SL6953423-111524

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (b)(1)(ii)
-URI http://asc.fasb.org/extlink&oid=121614798&loc=d3e15032-111544

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=121611835&loc=SL6953423-111524

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section S99
-Paragraph 4
-Subparagraph (SAB Topic 6.L.1)
-URI http://asc.fasb.org/extlink&oid=27010918&loc=d3e74567-122707

+ Details

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

- Definition

Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements.

+ References

+ Details

Name:	us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
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=121593590&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

- Details

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

- Details

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

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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

- Details

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

- Details

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

- Details

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

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ConsumerPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ResidentialPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_FinancialInstrumentAxis=slct_FamilyResidentialRealEstate1To4Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

LOANS - Composition of the Company's loan portfolio (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	$ 1,255,775		$ 1,032,089	$ 998,873
Less deferred loan origination fees, net	(5,776)		(2,114)
Total loans	1,249,999		1,029,975
Allowance for loan losses	(12,054)	$ (10,586)	(8,324)	(8,303)	$ (8,510)	$ (8,669)
Total loans, net	$ 1,237,945		$ 1,021,651
Less deferred loan origination fees, net	(0.21%)		(0.21%)
Percent of total	100.00%		100.00%
Real Estate Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, net	$ 1,086,592		$ 946,328
Percent of total	92.49%		91.89%
Other Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, net	$ 169,183		$ 85,761
Percent of total	7.72%		8.32%
Commercial Portfolio Segment [Member] \| Real Estate Loan [Member] \| Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	$ 516,112			449,209
Total loans	516,112		$ 459,115
Allowance for loan losses	(4,228)	(3,572)	(2,851)	(2,960)	(3,628)	(3,409)
Total loans, net	$ 516,112		$ 459,115
Percent of total	44.67%		44.58%
Commercial Portfolio Segment [Member] \| Real Estate Loan [Member] \| Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	$ 245,937			190,888
Total loans	245,937		$ 221,878
Allowance for loan losses	(2,295)	(2,132)	(1,737)	(1,493)	(1,595)	(1,385)
Total loans, net	$ 245,937		$ 221,878
Percent of total	21.99%		21.55%
Commercial Portfolio Segment [Member] \| Other Loan [Member] \| Commercial and industrial other loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	$ 161,643			78,360
Total loans	161,643		$ 75,748
Allowance for loan losses	(2,646)	(2,033)	(1,305)	(1,112)	(776)	(976)
Total loans, net	$ 161,643		$ 75,748
Percent of total	6.95%		7.35%
Commercial Portfolio Segment [Member] \| Other Loan [Member] \| Loans to individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, net	$ 7,469		$ 9,779
Percent of total	0.75%		0.95%
Commercial Portfolio Segment [Member] \| Other Loan [Member] \| Overdrafts [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, net	$ 71		$ 234
Percent of total	0.02%		0.02%
Consumer Portfolio Segment [Member] \| Real Estate Loan [Member] \| Multi-family residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	$ 77,877			60,665
Total loans	77,877		$ 69,124
Allowance for loan losses	(630)	(551)	(434)	(391)	(436)	(471)
Total loans, net	$ 77,877		$ 69,124
Percent of total	6.80%		6.71%
Residential Portfolio Segment [Member] \| HELOC [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, net	$ 49,271		$ 44,514
Percent of total	4.22%		4.32%
Residential Portfolio Segment [Member] \| Real Estate Loan [Member] \| 1- to- 4 family residential real estate loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	$ 197,395			161,670
Total loans	197,395		$ 151,697
Allowance for loan losses	(1,746)	(1,757)	(1,493)	(1,605)	(1,457)	(1,667)
Total loans, net	$ 197,395		$ 151,697
Percent of total	14.81%		14.73%
Residential Portfolio Segment [Member] \| Real Estate Loan [Member] \| HELOC [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	$ 49,271			47,786
Total loans	49,271		$ 44,514
Allowance for loan losses	$ (397)	$ (398)	$ (329)	$ (433)	$ (441)	$ (555)