11) Reinsurance, Commitments and Contingencies: Mortgage Loan Loss Settlements (Details) - USD ($)	Sep. 30, 2020	Dec. 31, 2019
Text Block [Abstract]
Funds reserved and accrued to settle investor related claims	$ 3,009,000	$ 4,046,000

Represents the monetary amount of Funds reserved and accrued to settle investor related claims, as of the indicated date.

No definition available.

Name:	snfc_FundsReservedAndAccruedToSettleInvestorRelatedClaims
Namespace Prefix:	snfc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant