Commitments and Contingencies - Mortgage Repurchase Liability Activity and Balances (Details) - USD ($) $ in Thousands	9 Months Ended
Sep. 30, 2024	Sep. 30, 2023
Mortgage repurchase liability:
Balance, beginning of period	$ 750	$ 809
Net recovery	(150)	(19)
Balance, end of period	$ 600	$ 790

Provision (recovery) charged for the period based on estimated losses for sold loans that may have to be subsequently repurchased and amounts that may have to be paid to reimburse certain investor losses due to breach of representations and warranties.

No definition available.

Name:	sbt_RecoveryOfMortgageRepurchaseLiability
Namespace Prefix:	sbt_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration