CREDIT FACILITIES (Details) - Secured Revolving Credit Facility [Member] $ in Millions	12 Months Ended
Dec. 31, 2016 USD ($)
Line of Credit Facility [Line Items]
Secured revolving credit agreement, maximum borrowing capacity	$ 75.0
Term of credit facility	5 years
Credit facility maturity date	Oct. 28, 2021
Percentage of inventory advance rate computed	60.00%
Percentage of inventory advance rate of net orderly liquidation value	85.00%
Eligible collateral under the credit facility	$ 64.4
Availability under line of credit	58.9
Total outstanding letters of credit	5.5
Outstanding borrowings	$ 0.0
Maximum [Member]
Line of Credit Facility [Line Items]
Percentage of eligible accounts receivable for borrowings	85.00%

Refers to the amount of eligible collateral letters of credit, based on borrowing base availability.

No definition available.

Name:	syx_EligibleCollateralUnderTheCreditFacility
Namespace Prefix:	syx_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Refers to the amount of outstanding advances.

+ References

No definition available.

+ Details

Name:	syx_OutstandingAdvances
Namespace Prefix:	syx_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The percentage of eligible accounts receivable for borrowings under the agreement.

+ References

No definition available.

+ Details

Name:	syx_PercentageOfEligibleAccountsReceivableForBorrowings
Namespace Prefix:	syx_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Refers to percentage of inventory advance rate computed as the lesser of NOVL (Net Orderly Liquidation Value).

+ References

No definition available.

+ Details

Name:	syx_PercentageOfInventoryAdvanceRateComputed
Namespace Prefix:	syx_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Refers to percentage of inventory advance rate computed of NOVL (Net Orderly Liquidation Value).

+ References

No definition available.

+ Details

Name:	syx_PercentageOfInventoryAdvanceRateOfNOVL
Namespace Prefix:	syx_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentTerm
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
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://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

+ 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_CreditFacilityAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: