RELATED PARTY TRANSACTIONS (Details) - Affiliate of Sponsor - Administrative Support Agreement - USD ($)	3 Months Ended	6 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018
Administrative Support Agreement
Monthly service fees			$ 10,000
Service fees incurred	$ 30,000	$ 30,000	$ 90,000

Represents the amount of service fees incurred for office space, utilities and administrative support.

No definition available.

Name:	fsacu_RelatedPartyTransactionServiceFeesIncurred
Namespace Prefix:	fsacu_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration