Borrowed Funds (Subordinated Debentures Owed to Unconsolidated Subsidiary Trusts) (Narrative) (Details)	1 Months Ended			12 Months Ended
	Dec. 31, 2005 USD ($)	Mar. 31, 2004 USD ($)	Oct. 31, 2002 USD ($)	Dec. 31, 2019 USD ($) trust	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Debt Instrument [Line Items]
Number of Statutory Business Trusts | trust				3
Subordinated debentures owed to unconsolidated subsidiary trusts				$ 19,589,000	$ 19,589,000
Ownership percentage				100.00%
Proceeds from issuance of common stock, net of issuance costs				$ 159,000	$ 237,000	$ 10,000
Trust preferred securities limited to tier one capital elements, Nnt of goodwill				25.00%
Sfg Capital Trust I [Member]
Debt Instrument [Line Items]
Proceeds from issuance or sale of equity			$ 3,500,000
Proceeds from issuance of common stock, net of issuance costs			109,000
Payments to acquire investments			$ 3,610,000
Basis spread on variable rate			3.45%
Sfg Capital Trust Ii [Member]
Debt Instrument [Line Items]
Proceeds from issuance or sale of equity		$ 7,500,000
Proceeds from issuance of common stock, net of issuance costs		232,000
Payments to acquire investments		$ 7,730,000
Basis spread on variable rate		2.80%
Sfg Capital Trust Iii [Member]
Debt Instrument [Line Items]
Proceeds from issuance or sale of equity	$ 8,000,000
Proceeds from issuance of common stock, net of issuance costs	248,000
Payments to acquire investments	$ 8,250,000
Basis spread on variable rate	1.45%