Name:	sbsi_InterestIncomeOtherStocksAndBonds
Namespace Prefix:	sbsi_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

The amount of interest income and other income recognized during the period. Included in this element is interest derived from investments in debt securities, cash and cash equivalents, and other investments which reflect the time value of money or transactions in which the payments are for the use or forbearance of money and other income from ancillary business-related activities (that is, excluding major activities considered part of the normal operations of the business).

No definition available.

Name:	us-gaap_InterestAndOtherIncome
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Amount of operating interest income, including amortization and accretion of premiums and discounts, on securitized, pass-through debt securities collateralized by real estate mortgage loans.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04.2)
-URI http://asc.fasb.org/extlink&oid=120399700&loc=SL114874048-224260

Name:	us-gaap_InterestIncomeSecuritiesMortgageBacked
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Interest income on securities issued by US government agencies not including US Treasury Securities.

Name:	us-gaap_InterestIncomeSecuritiesOtherUSGovernment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Interest income, including any amortization and accretion (as applicable) of discounts and premiums, derived from debt securities issued by municipal governments, local taxing districts and US state government agencies.

Name:	us-gaap_InterestIncomeSecuritiesStateAndMunicipal
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Interest income on US treasury securities. US treasury securities are negotiable debt obligations of the US government, secured by its full faith and credit and issued at various schedules and maturities. The income from treasury securities is exempt from state and local, but not federal, taxes. There are three types of securities issued by the US treasury (bonds, bills, and notes), which are distinguished by the amount of time from the initial sale of the bond to maturity.

Name:	us-gaap_InterestIncomeSecuritiesUSTreasury
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- References

No definition available.