Line of credit facility, commitment extension fee percentage.

No definition available.

Name:	sss_LineOfCreditFacilityCommitmentExtensionFeePercentage
Namespace Prefix:	sss_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of one year extensions.

+ References

No definition available.

+ Details

Name:	sss_NumberOfOneYearExtensions
Namespace Prefix:	sss_
Data Type:	xbrli:positiveIntegerItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	sss_UnsecuredLineOfCreditAndTermNotesLineItems
Namespace Prefix:	sss_
Data Type:	xbrli:stringItemType
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

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22(a)(1))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Maximum contractual interest rate for funds borrowed, under the debt agreement.

+ References

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMaximum
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

The fee, expressed as a percentage of the line of credit facility, for the line of credit facility regardless of whether the facility has been used.

+ References

No definition available.

+ Details

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

- Definition

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

+ References

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

-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

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 22

-Article 5

+ Details

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

- Definition

The effective interest rate at the end of the reporting period.

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityInterestRateAtPeriodEnd
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- 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

- Definition

Including the current and noncurrent portions, aggregate carrying amount of all types of notes payable, as of the balance sheet date, with initial maturities beyond one year or beyond the normal operating cycle, if longer.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.16)

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 20, 22

-Article 5

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.16)

-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 13, 16

-Article 9

+ Details

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

- Definition

The cash inflow during the period from additional borrowings in aggregate debt. Includes proceeds from short-term and long-term debt.

+ References

No definition available.

+ Details

Name:	us-gaap_ProceedsFromIssuanceOfDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Unsecured Line of Credit and Term Notes - Additional Information (Detail) (USD $)	3 Months Ended			3 Months Ended	12 Months Ended	3 Months Ended			3 Months Ended			3 Months Ended	0 Months Ended
	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2014 Maximum [Member]	Mar. 31, 2014 Maturity in August 2021 [Member]	Dec. 31, 2011 Maturity in August 2021 [Member]	Mar. 31, 2014 Maturity in April 2016 [Member]	Mar. 31, 2014 Maturity on June 4, 2020 [Member]	Jun. 04, 2013 Maturity on June 4, 2020 [Member]	Mar. 31, 2014 Maturity on June 4, 2018 [Member] MortgageLoan	Dec. 31, 2013 Maturity on June 4, 2018 [Member]	Jun. 04, 2013 Term Loan Due in June, 4 2020 [Member]	Mar. 31, 2014 Maturity in April, 2024 [Member]	Apr. 08, 2014 Subsequent Event [Member] Maturity in April, 2024 [Member]
Unsecured Line Of Credit And Term Notes [Line Items]
Additional secured commitments	$ 575,000,000	$ 575,000,000				$ 150,000,000		$ 225,000,000			$ 100,000,000
Basis spread over LIBOR							1.65%		1.50%
Revolving line of credit facility agreement	175,000,000		250,000,000
Facility fee									0.20%
Interest rate, line of credit facility									1.65%	1.67%
Amount available on unsecured line of credit									59,300,000
Number of one year extensions									2
Line of credit facility, expiration date				Aug. 05, 2021		Apr. 13, 2016	Jun. 04, 2020		Jun. 04, 2018			Apr. 08, 2024
Extension facility fee	0.125%
Letters of credit outstanding amount									700,000
Additional secured term note					$ 100,000,000								$ 175,000,000
Increase in interest rate on term loan					7.29%	8.13%							6.283%
Term note stated interest rate					5.54%	6.38%							4.533%