Related Party Transactions (Details)	12 Months Ended
Dec. 31, 2019 USD ($) item	Dec. 31, 2018 USD ($)
Related party loan activity [Roll forward]
Deposits	$ 661,049,000	$ 779,506,000
Board of Directors [Member]
Related party loan activity [Roll forward]
Beginning balance	3,628,000	6,455,000
Additions	13,751,000	771,000
Repayments	(28,000)	(3,598,000)
Change in Directors/Officers	2,181,000
Ending balance	19,532,000	3,628,000
Deposits	$ 5,800,000	3,900,000
President [Member] \| Law Firm, Bank Partner [Member]
Related party loan activity [Roll forward]
Period for lease agreement with subsidiary	5 years
Number of additional term for which period of lease agreement increase \| item	3
Total lease payments received by the subsidiary	$ 287,000	281,000
Related party transaction fees for services	149,000	158,000
Deposits	$ 1,400,000	$ 270,000

Reflects the amount of changes made to related party loans, due to changes in directors and officers.

No definition available.

Name:	svbi_LoansAndLeasesReceivableRelatedPartiesChangesInDirectorsAndOfficers
Namespace Prefix:	svbi_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

This element represents the number of term for which period of lease agreement increase for another five years.

+ References

No definition available.

+ Details

Name:	svbi_NumberOfAdditionalTermForWhichPeriodOfLeaseAgreementIncrease
Namespace Prefix:	svbi_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Date of lease agreement or expiration of arrangements with a related party (for example, but not limited to, leasing and debt arrangements between related parties), in CCYY-MM-DD format.

+ References

No definition available.

+ Details

Name:	svbi_TermOfLeaseAgreement
Namespace Prefix:	svbi_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

The aggregate of all deposit liabilities held by the entity, including foreign and domestic, interest and noninterest bearing; may include demand deposits, saving deposits, Negotiable Order of Withdrawal (NOW) and time deposits among others.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.12)
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

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

- Definition

For an unclassified balance sheet, reflects the carrying amount of unpaid loan amounts due from related parties at the balance sheet date.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 850
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39549-107864

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(e))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

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

- Definition

Reflects the amount of new advances made to related parties in the form of loan and lease receivables.

+ References

+ Details

Name:	us-gaap_LoansAndLeasesReceivableRelatedPartiesAdditions
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of cash inflow from related parties which reduce the amount of loans and leases receivable due from related parties.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(7)(e)(1)(i))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3179-108585

+ Details

Name:	us-gaap_LoansAndLeasesReceivableRelatedPartiesProceeds
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

+ Details

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

- Definition

The cash inflow associated with the collection of receivables arising from the lease of real estate, equipment or other fixed assets for a specified time in exchange for payment, usually in the form of rent; excludes proceeds from sales-type lease transactions, which are classified as operating activities.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3179-108585

+ Details

Name:	us-gaap_ProceedsFromCollectionOfLeaseReceivables
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Expenses recognized resulting from transactions (excluding transactions that are eliminated in consolidated or combined financial statements) with related party.

+ References

+ Details

Name:	us-gaap_RelatedPartyTransactionExpensesFromTransactionsWithRelatedParty
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=svbi_BoardOfDirectorsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionAxis=srt_PresidentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=srt_AffiliatedEntityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: