Legal Proceedings (Details)	Mar. 31, 2019 state
Commitments and Contingencies Disclosure [Abstract]
Number of states seeking recovery of unclaimed property	26
Number of states requesting payment	21

The number of states being audited and seeking recovery of unclaimed property.

No definition available.

Name:	syx_NumberOfStatesSeekingRecoveryOfUnclaimedProperty
Namespace Prefix:	syx_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant