XML 113 R102.htm IDEA: XBRL DOCUMENT
v3.7.0.1

Subsequent Events (Details) | 3 Months Ended
--- | ---
Mar. 31, 2017 item
Subsequent Events [Abstract] |
Number of types of subsequent events | 2

X
- Definition Number of types of subsequent events. + References No definition available. + Details
Name: | sf_NumberOfTypesOfSubsequentEvents
Namespace Prefix: | sf_
Data Type: | xbrli:positiveIntegerItemType
Balance Type: | na
Period Type: | duration

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