XML 60 R55.htm IDEA: XBRL DOCUMENT
v3.19.3

Nature of Operations, Basis of Presentation, and Summary of Significant Accounting Policies (Narrative) (Details) | Sep. 30, 2019
--- | ---
North Shore Aviation Holdings LLC [Member] |
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items] |
Noncontrolling Interest, Ownership Percentage by Parent | 27.50%

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The parent entity's interest in net assets of the subsidiary, expressed as a percentage. + References No definition available. + Details
Name: | us-gaap_MinorityInterestOwnershipPercentageByParent
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | srt_OwnershipAxis=sf_NorthShoreAviationHoldingsLLCMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |