Fair value amount of debt instrument that was repurchased during the period.

No definition available.

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The increase (decrease) to the mortgage repurchase liability recorded during the period.

+ References

No definition available.

+ Details

Name:	sbt_IncreaseDecreaseMortgageRepurchaseLiability
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Probable losses accrued in connection with the repurchase of mortgage loans sold.

+ References

No definition available.

+ Details

Name:	sbt_MortgageLoansRepurchaseLiability
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Number of loan pools negotiated to be repurchased during the period.

+ References

No definition available.

+ Details

Name:	sbt_NumberOfLoanPoolsNegotiatedToBeRepurchased
Namespace Prefix:	sbt_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of loans offered to each of investors to repurchase

+ References

No definition available.

+ Details

Name:	sbt_PercentageOfLoansOfferedToEachOfInvestorsToRepurchase
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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

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- 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

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The adjustment to the carrying value of the rights retained or purchased to service mortgages. These adjustments are made when the estimate of the fair value is changed. This element is a noncash adjustment to net income when calculating net cash generated by operating activities using the indirect method.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3602-108585

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 50
-Section 50
-Paragraph 4
-Subparagraph (a)(6)
-URI http://asc.fasb.org/extlink&oid=116651436&loc=d3e122739-111746

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of noninterest expense classified as other.

+ References

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 210.9-04.14)
-URI http://asc.fasb.org/extlink&oid=120399700&loc=SL114874048-224260

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

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Namespace Prefix:
Data Type:	na
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Commitments and Contingencies - Advantage Loan Program Loans Sold (Details) $ in Thousands	1 Months Ended	7 Months Ended	12 Months Ended
	May 31, 2020 USD ($) item	Dec. 31, 2020 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Commitments and Contingencies
Unpaid principal balance		$ 2,434,356	$ 2,434,356	$ 2,891,530
Loss related to fair value discount recorded in other non-interest expense			5,741	7,342	$ 7,220
Advantage Loan Program
Commitments and Contingencies
Number of loan pools negotiated to be repurchased \| item	2
Unpaid principal balance		429,816	429,816	670,243
Outstanding principal balance of loans repurchased	$ 38,704	30,934	69,638
Mortgage loan repurchase liability		2,527	2,527	7,823
Loss related to fair value discount recorded in other non-interest expense	136	$ 135	$ 271
Percentage of loans offered to each of investors to repurchase		100.00%	100.00%
Loss charged against mortgage repurchase liability		$ 651	$ 651
Disposition of mortgage servicing rights	$ 428	361
Residential real estate
Commitments and Contingencies
Unpaid principal balance		562,139	562,139	759,568
Mortgage loan repurchase liability		$ 9,699	$ 9,699	$ 7,823