XML 120 R109.htm IDEA: XBRL DOCUMENT
v3.19.2

Segment Reporting (Schedule Of Operating Information, Segment) (Parenthetical) (Details) | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2019 | Jun. 30, 2018 | Jun. 30, 2019 | Jun. 30, 2018
Segment Reporting [Abstract] |  |  |  |
Net revenues accounted for by individual client, maximum percentage | 10.00% | 10.00% | 10.00% | 10.00%

X
- Definition Net revenues accounted for by individual client, maximum percentage. + References No definition available. + Details
Name: | sf_NetRevenuesAccountedForByIndividualClientMaximumPercentage
Namespace Prefix: | sf_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

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- References No definition available. + Details
Name: | us-gaap_SegmentReportingAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration