Percentage points deducted from the reference rate to compute the variable rate on the debt instrument.

No definition available.

Name:	sret_DebtInstrumentBasisReductionOnVariableRate
Namespace Prefix:	sret_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the number of letter of credit secured under the debt instrument.

+ References

No definition available.

+ Details

Name:	sret_DebtInstrumentNumberOfLettersOfCreditSecured
Namespace Prefix:	sret_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the number of properties out of compliance with the debt covenant.

+ References

No definition available.

+ Details

Name:	sret_NumberOfPropertiesOutOfComplianceWithDebtCovenant
Namespace Prefix:	sret_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

Name:	us-gaap_LettersOfCreditOutstandingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Date the credit facility terminates, in CCYY-MM-DD format.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_LineOfCreditFacilityExpirationDate1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- 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

Name:	us-gaap_LineOfCreditFacilityLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	us-gaap_LineOfCreditFacilityAxis=sret_WellsFargoBankMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=sret_OneMonthLondonInterbankOfferedRateLiborMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LineOfCreditFacilityAxis=sret_BremerBankMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LineOfCreditFacilityAxis=sret_BremerBankAgreementOneMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_PrimeRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LineOfCreditFacilityAxis=sret_BremerBankAgreementTwoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=sret_FloatingLondonInterbankOfferedRateLiborMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LineOfCreditFacilityAxis=sret_AgreementWithBankOfWestMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_LondonInterbankOfferedRateLIBORMember
Namespace Prefix:
Data Type:	na
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Lines of Credit - Additional Information (Details) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2020 USD ($) item	Dec. 31, 2019 property
Lines of Credit
Number of letters of credit secured \| item	2
Letters of credit total	$ 1,216
Unused line of credit	30,199
Wells Fargo Bank
Lines of Credit
Agreed line of credit	$ 18,300
Expiration date	Jun. 01, 2021
Wells Fargo Bank \| 1-Month LIBOR
Lines of Credit
Variable interest rate of line of credit	2.25%
Bremer Bank
Lines of Credit
Number of properties out of compliance with debt covenant \| property		3
Bremer Bank Agreement One
Lines of Credit
Agreed line of credit	$ 4,915
Expiration date	Jun. 01, 2022
Bremer Bank Agreement One \| Prime Rate
Lines of Credit
Basis reduction on variable rate (as a percent)	0.50%
Bremer Bank Agreement Two
Lines of Credit
Agreed line of credit	$ 5,000
Expiration date	Jun. 01, 2022
Bremer Bank Agreement Two \| Floating LIBOR
Lines of Credit
Variable interest rate of line of credit	2.00%
Bank of the West
Lines of Credit
Agreed line of credit	$ 3,200
Expiration date	Nov. 01, 2020
Bank of the West \| LIBOR
Lines of Credit
Variable interest rate of line of credit	2.04%