Deposits (Deposits outstanding by type) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Deposits, by Type [Abstract]
Checking Accounts	$ 143,422,150us-gaap_DemandDepositAccounts	$ 136,695,876us-gaap_DemandDepositAccounts
Money Market Accounts	234,819,052us-gaap_DepositsMoneyMarketDeposits	240,631,708us-gaap_DepositsMoneyMarketDeposits
Statement Savings Accounts	28,622,933us-gaap_DepositsSavingsDeposits	24,485,648us-gaap_DepositsSavingsDeposits
Total	406,864,135sfdl_DepositsExcludingTimeDeposits	401,813,232sfdl_DepositsExcludingTimeDeposits
Certificate Accounts	253,251,029us-gaap_TimeDeposits	256,883,540us-gaap_TimeDeposits
Total Deposits	660,115,164us-gaap_Deposits	658,696,772us-gaap_Deposits
Weighted Average Rate Domestic Deposit Liabilities [Abstract]
Checking Accounts, Weighted Rate	0.03%	0.04%
Money Market Accounts, Weighted Rate	0.19%	0.28%
Statement Savings Accounts, Weighted Rate	0.10%	0.10%
Total, Weighted Rate	0.13%	0.19%
Certificate Accounts, Weighted Rate	0.79%	0.83%
Total Deposit, Weighted Rate	0.38%	0.44%
Interest Rate Range Domestic Deposit Liabilities [Abstract]
Interest-bearing Domestic Deposit, Brokered	38,800,000	25,600,000
Weighted Average Rate Domestic Deposit, Brokered	1.14%	1.23%
Interest Bearing Domestic Deposit Maturities, Brokered, Next Twelve Months	1,900,000
Time Deposits, $100,000 or More	140,000,000us-gaap_TimeDeposits100000OrMore	129,900,000us-gaap_TimeDeposits100000OrMore
Overdrafts reclassified to loans	132,000	133,000
Minimum
Interest Rate Range Domestic Deposit Liabilities [Abstract]
Interest Rate Domestic Deposit, Checking	0.00%	0.00%
Interest Rate Domestic Deposit, Money Market	0.10%	0.10%
Interest Rate Domestic Deposit, Savings	0.00%	0.00%
Interest Rate Domestic Deposit, Excluding Time Deposits	0.00%	0.00%
Interest Rate Domestic Deposit, Time Deposits	0.05%	0.05%
Interest Rate Domestic Deposit	0.00%	0.00%
Maximum
Interest Rate Range Domestic Deposit Liabilities [Abstract]
Interest Rate Domestic Deposit, Checking	0.15%	0.15%
Interest Rate Domestic Deposit, Money Market	0.20%	0.30%
Interest Rate Domestic Deposit, Savings	0.10%	0.10%
Interest Rate Domestic Deposit, Excluding Time Deposits	0.20%	0.30%
Interest Rate Domestic Deposit, Time Deposits	3.01%	3.25%
Interest Rate Domestic Deposit	3.01%	3.25%
0.00 – 1.99%
Deposits, by Type [Abstract]
Certificate Accounts	227,473,082	226,750,180
0.00 – 1.99% \| Minimum
Interest Rate Range Domestic Deposit Liabilities [Abstract]
Interest Rate Domestic Deposit, Time Deposits	0.00%
0.00 – 1.99% \| Maximum
Interest Rate Range Domestic Deposit Liabilities [Abstract]
Interest Rate Domestic Deposit, Time Deposits	1.99%
2.00 – 2.99%
Deposits, by Type [Abstract]
Certificate Accounts	25,605,349	28,848,252
2.00 – 2.99% \| Minimum
Interest Rate Range Domestic Deposit Liabilities [Abstract]
Interest Rate Domestic Deposit, Time Deposits	2.00%
2.00 – 2.99% \| Maximum
Interest Rate Range Domestic Deposit Liabilities [Abstract]
Interest Rate Domestic Deposit, Time Deposits	2.99%
3.00 – 3.99%
Deposits, by Type [Abstract]
Certificate Accounts	$ 172,598	$ 1,285,108
3.00 – 3.99% \| Minimum
Interest Rate Range Domestic Deposit Liabilities [Abstract]
Interest Rate Domestic Deposit, Time Deposits	3.00%
3.00 – 3.99% \| Maximum
Interest Rate Range Domestic Deposit Liabilities [Abstract]
Interest Rate Domestic Deposit, Time Deposits	3.99%

Deposits, Excluding Time Deposits

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Interest Bearing Domestic Deposit Maturities, Brokered, Next Twelve Months

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Interest Rate Domestic Deposit

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Interest Rate Domestic Deposit, Checking

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Interest Rate Domestic Deposit, Excluding Time Deposits

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Interest Rate Domestic Deposit, Money Market

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Interest Rate Domestic Deposit, Savings

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Interest Rate Domestic Deposit, Time Deposits

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Weighted Average Rate Domestic Deposit, Excluding Time Deposits

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- Definition

The amount of money in accounts that may bear interest and that the depositor is entitled to withdraw at any time without prior notice.

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- Definition

Amount of deposits held by the entity that have been reclassified as loan balances receivable, for example, but not limited to, overdrafts receivable.

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The aggregate of all deposit liabilities held by the entity, including foreign and domestic, interest and noninterest bearing; may include demand deposits, saving deposits, Negotiable Order of Withdrawal (NOW) and time deposits among others.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.12)

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 12

-Article 9

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Amount of deposits in accounts that offer many of the same services as checking accounts although transactions may be somewhat more limited, share some of the characteristics of a money market fund and are insured by the Federal government, also known as money market accounts.

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Amount of interest bearing deposits with no stated maturity, which may include passbook and statement savings accounts and money-market deposit accounts (MMDAs).

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Amount of interest-bearing domestic third-party deposits placed by or through the assistance of a deposit broker, also known as brokered deposit liabilities.

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Amount of deposits that cannot be withdrawn before a set date without penalty or for which notice of withdrawal is required. Time deposits include, but are not limited to, certificates of deposits, individual retirement accounts and open accounts.

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The aggregate amount of domestic and foreign time deposit liabilities (including certificates of deposits, individual retirement accounts and open accounts) in denominations of $100,000 or more.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 405

-Section 50

-Paragraph 1

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6479006&loc=d3e64164-112818

Reference 2: http://www.xbrl.org/2003/role/presentationRef

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-Name Industry Guide

-Number 3

-Section V

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The weighted average interest rate for all domestic deposit liabilities.

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The weighted average interest rate for domestic brokered deposit liabilities.

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The weighted average interest rate for domestic certificates of deposit liabilities.

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The weighted average interest rate for domestic checking deposit liabilities.

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The weighted average interest rate for domestic money market demand account deposit liabilities.

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The weighted average interest rate for domestic savings deposit liabilities.

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