COMMITMENTS AND CONTINGENCIES (Details) - USD ($)		9 Months Ended
Jul. 24, 2017	Dec. 31, 2017
COMMITMENTS AND CONTINGENCIES
Percentage of deferred discount to underwriters		3.50%
Deferred underwriting fees	$ 16,100,000	$ 16,100,000

Represents the percentage of deferred discount on the gross proceeds of the Public offering payable to the underwriters upon the Company's completion of an Initial Business Combination.

No definition available.

Name:	fsacu_PercentageOfDeferredDiscountToUnderwriters
Namespace Prefix:	fsacu_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration