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Namespace Prefix:	stl_
Data Type:	xbrli:monetaryItemType
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The total amount of proceeds received for the call of securities, categorized neither as held-to-maturity nor trading securities, during the reporting period.

No definition available.

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Namespace Prefix:	stl_
Data Type:	xbrli:monetaryItemType
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This item represents the gross loss realized on the call of debt or equity securities categorized neither as held-to-maturity nor trading securities.

No definition available.

Name:	stl_AvailableForSaleSecuritiesGrossRealizedLossesCall
Namespace Prefix:	stl_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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This item represents the gross profit realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

-Paragraph 9

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6872113&loc=d3e27357-111563

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

-Paragraph 21

-Subparagraph a

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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Data Type:	xbrli:monetaryItemType
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The total amount of proceeds received for the sale of securities, categorized neither as held-to-maturity nor trading securities, during the reporting period.

Name:	us-gaap_AvailableForSaleSecuritiesGrossRealizedGainsLossesSaleProceeds
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
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This item represents the gross loss realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities.