Derivatives and Hedging Activities - Credit-Risk Related Contingent Features (Details) $ in Thousands	Sep. 30, 2022 USD ($)
Credit-risk-related Contingent Features
Termination value of interest rate derivatives in asset position	$ 14,356

The aggregate fair value amounts of derivative instruments that contain credit-risk-related contingent features that are in a net asset position at the end of the reporting period.

No definition available.

Name:	sret_DerivativeNetAssetPositionAggregateFairValue
Namespace Prefix:	sret_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant