Name:	stfc_ExcessCedingCommission
Namespace Prefix:	stfc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Percentage Ceded To Reinsurers

No definition available.

Name:	stfc_PercentageCededToReinsurers
Namespace Prefix:	stfc_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Excess commission returned to the Company from a reinsurer in the form of ceded profit commission

No definition available.

Name:	stfc_ProfitCommission
Namespace Prefix:	stfc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Quota Share Agreement Period

No definition available.

Name:	stfc_QuotaShareAgreementPeriod
Namespace Prefix:	stfc_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

HO QS Reinsurance Arrangement, Participating Reinsurers' Margin

No definition available.

Name:	stfc_ReinsuranceArrangementParticipatingReinsurersMargin
Namespace Prefix:	stfc_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Reinsurance [Line Items]

No definition available.

Name:	stfc_ReinsuranceLineItems
Namespace Prefix:	stfc_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Carrying amount of premiums written on insurance contracts that have not been earned as of the balance sheet date.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.(a),13(a)(2))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 16
-Article 12