GOODWILL, OTHER INTANGIBLE ASSETS, AND ASSET IMPAIRMENT CHARGES - Goodwill (Details)	Dec. 31, 2019	Dec. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Percentage of fair value in excess of carrying value	26.00%
Percentage of fair value in excess of carrying value		23.00%

Reporting Unit, Percentage of Fair value In Excess Of Carrying Value, Intangible Assets

No definition available.

Name:	spxf_ReportingUnitPercentageofFairvalueInExcessOfCarryingValueIntangibleAssets
Namespace Prefix:	spxf_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant