SECURITIES AVAILABLE-FOR-SALE (Narrative) (Details) (USD $)
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12 Months Ended |
Dec. 31, 2014
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Dec. 31, 2013
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Dec. 31, 2012
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Schedule of Available-for-sale Securities [Line Items] |
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Proceeds from sale of available-for-sale securities |
$ 26,700,000us-gaap_ProceedsFromSaleOfAvailableForSaleSecurities |
$ 700,000us-gaap_ProceedsFromSaleOfAvailableForSaleSecurities |
$ 56,400,000us-gaap_ProceedsFromSaleOfAvailableForSaleSecurities |
Number of securities with unrealized gross losses |
134bsrr_NumberOfSecuritiesWithUnrealizedGrossLosses |
197bsrr_NumberOfSecuritiesWithUnrealizedGrossLosses |
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Amortized Cost |
504,564,000us-gaap_AvailableForSaleSecuritiesAmortizedCost |
424,315,000us-gaap_AvailableForSaleSecuritiesAmortizedCost |
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Other Contractual Obligations and Short-Term Borrowing Arrangements [Member] |
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Schedule of Available-for-sale Securities [Line Items] |
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Pledged financial instruments, not separately reported, securities |
137,160,000us-gaap_PledgedFinancialInstrumentsNotSeparatelyReportedSecuritiesPledged / us-gaap_UnderlyingAssetClassAxis = bsrr_OtherContractualObligationsAndShortTermBorrowingArrangementsMember |
162,393,000us-gaap_PledgedFinancialInstrumentsNotSeparatelyReportedSecuritiesPledged / us-gaap_UnderlyingAssetClassAxis = bsrr_OtherContractualObligationsAndShortTermBorrowingArrangementsMember |
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Pledged assets separately reported, securities pledged as collateral, at fair value |
140,611,000us-gaap_PledgedAssetsSeparatelyReportedSecuritiesPledgedAsCollateralAtFairValue / us-gaap_UnderlyingAssetClassAxis = bsrr_OtherContractualObligationsAndShortTermBorrowingArrangementsMember |
164,390,000us-gaap_PledgedAssetsSeparatelyReportedSecuritiesPledgedAsCollateralAtFairValue / us-gaap_UnderlyingAssetClassAxis = bsrr_OtherContractualObligationsAndShortTermBorrowingArrangementsMember |
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U.S. Government agencies [Member] |
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Schedule of Available-for-sale Securities [Line Items] |
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Proceeds from sale of available-for-sale securities |
502,000us-gaap_ProceedsFromSaleOfAvailableForSaleSecurities / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_USGovernmentAgenciesDebtSecuritiesMember |
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Number of securities with realized gross gains |
59bsrr_NumberOfSecuritiesWithRealizedGrossGains / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_USGovernmentAgenciesDebtSecuritiesMember |
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Equity Securities [Member] |
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Schedule of Available-for-sale Securities [Line Items] |
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Proceeds from sale of available-for-sale securities |
238,000us-gaap_ProceedsFromSaleOfAvailableForSaleSecurities / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = bsrr_EquitySecurityMember |
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Number of securities with realized gross gains |
1bsrr_NumberOfSecuritiesWithRealizedGrossGains / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = bsrr_EquitySecurityMember |
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Amortized Cost |
1,210,000us-gaap_AvailableForSaleSecuritiesAmortizedCost / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = bsrr_EquitySecurityMember |
1,336,000us-gaap_AvailableForSaleSecuritiesAmortizedCost / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = bsrr_EquitySecurityMember |
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Other Securities [Member] |
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Schedule of Available-for-sale Securities [Line Items] |
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Number of securities with realized gross gains |
7bsrr_NumberOfSecuritiesWithRealizedGrossGains / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_OtherDebtSecuritiesMember |
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Available-for-sale securities, gross realized gain (loss) |
72,000us-gaap_AvailableForSaleSecuritiesGrossRealizedGainLossNet / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_OtherDebtSecuritiesMember |
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States and Political Subdivisions [Member] |
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Schedule of Available-for-sale Securities [Line Items] |
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Amortized Cost |
98,056,000us-gaap_AvailableForSaleSecuritiesAmortizedCost / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_USStatesAndPoliticalSubdivisionsMember |
97,361,000us-gaap_AvailableForSaleSecuritiesAmortizedCost / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_USStatesAndPoliticalSubdivisionsMember |
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States and Political Subdivisions [Member] | Arizona [Member] |
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Schedule of Available-for-sale Securities [Line Items] |
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Amortized Cost |
$ 3,800,000us-gaap_AvailableForSaleSecuritiesAmortizedCost / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_USStatesAndPoliticalSubdivisionsMember / bsrr_StateOfIssuanceAxis = bsrr_ArizonaStateMember |
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