INVENTORIES - Schedule of Service Parts Inventories (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Mar. 31, 2018	Sep. 30, 2017
Service Inventories [Abstract]
Finished goods	$ 13,302	$ 14,863
Component parts	5,340	7,026
Total service inventories	$ 18,642	$ 21,889	$ 19,915

Carrying amount of completed service parts merchandise or goods expected to be sold within one year or operating cycle, if longer.

No definition available.

Name:	qmco_ServicePartsInventoriesFinishedGoods
Namespace Prefix:	qmco_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant