Noncontrolling Interests - Additional Information (Detail) - shares	3 Months Ended	12 Months Ended
Sep. 30, 2018	Dec. 31, 2017
Noncontrolling Interest [Abstract]
Number of Group A Units canceled pursuant to the Relinquishment Agreement		3,000,000.0
Group A Units relinquished by former executive managing director	350,000

Number of Group A Units canceled pursuant to the Relinquishment Agreement

No definition available.

Name:	scu_NumberOfGroupAUnitsCanceledPursuantToTheRelinquishmentAgreement
Namespace Prefix:	scu_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration