XML 62 R50.htm IDEA: XBRL DOCUMENT
v3.21.1

3) Investments: Summary of Interest not accrued on non-performing mortgage loans (Details) - USD ($) | Mar. 31, 2021 | Dec. 31, 2020
--- | --- | ---
Text Block [Abstract] |  |
Interest not accrued on non-performing loans | $ 321,000 | $ 491,000

X
- Definition Represents the monetary amount of Interest not accrued on non-performing loans, as of the indicated date. + References No definition available. + Details
Name: | snfc_InterestNotAccruedOnNonPerformingLoans
Namespace Prefix: | snfc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

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