v2.4.0.8

Borrowings (Details Textual) (USD $)	9 Months Ended				9 Months Ended	1 Months Ended			0 Months Ended
Borrowings (Details Textual) (USD $)	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2014 Fixed Interest	Sep. 30, 2014 Variable Interest Rate	Sep. 30, 2014 First Citizens (TN) Statutory Trust II	Jun. 17, 2005 First Citizens (TN) Statutory Trust III	Mar. 31, 2005 First Citizens (TN) Statutory Trust III	Mar. 17, 2005 First Citizens (TN) Statutory Trust III	Jun. 15, 2007 First Citizens (TN) Statutory Trust IV	Mar. 31, 2007 First Citizens (TN) Statutory Trust IV
Subordinated Borrowing [Line Items]
Common stock held in First Citizens (TN) Statutory Trust III							100.00%			100.00%
Floating rate trust preferred securities sold (in shares)								5,000		5,000
Floating rate trust preferred securities sold at liquidation amount (in dollar per share)								$ 1,000		$ 1,000
Floating rate trust preferred securities sold amount								$ 5,000,000		$ 5,000,000
Trust preferred securities floating interest rate						4.84%			7.10%
Description of reference rate basis						1.80			LIBOR
Interest payment Term						30 years			30 years
Tier I Capital maximum limit percentage	25.00%
Total saving for refinance the debt issued First Citizens (TN) Statutory Trust II					92,500
Interest accrues at rate									1.75%
Secured advances from the FHLB	46,500,000	40,900,000
Interest rate ranging from			0.54%
Interest rate ranging to			7.05%
Total Advances require repayment if the call feature is exercised	14,000,000
Obligations secured by loans- Total				389,000,000
Additional borrowing capacity				$ 95,100,000

Represent as a advance repayment from federal home loan banks if call feature exercised.

+ References

No definition available.

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Namespace Prefix:	fizn_
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Balance Type:	credit
Period Type:	instant

- Definition

Represents percentage of common stock held in trust.

+ References

No definition available.

+ Details

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- Definition

Description of the payment terms of the debt instrument (for example, whether periodic payments include principal and frequency of payments) and discussion about any contingencies associated with the payment.

+ References

No definition available.

+ Details

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- Definition

The per share liquidation preference (or restrictions) of nonredeemable preferred stock (or preferred stock redeemable solely at the option of the issuer) that has a preference in involuntary liquidation considerably in excess of the par or stated value of the shares. The liquidation preference is the difference between the preference in liquidation and the par or stated values of the share.

+ References

No definition available.

+ Details

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Data Type:	num:perShareItemType
Balance Type:	na
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- Definition

Value of the difference between preference in liquidation and the par or stated values of the preferred shares.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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- Definition

Represents the number of trust preferred securities sold as on that date.

+ References

No definition available.

+ Details

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Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the total savings made from sale of shares for the purpose of refinance of debt.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Represents the aggregate percentage of Tier One capital maximum limit.

+ References

No definition available.

+ Details

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- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

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- Definition

The reference rate for the variable rate of the debt instrument, such as LIBOR or the US Treasury rate and the maturity of the reference rate used, such as three months or six months LIBOR.

+ References

No definition available.

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Data Type:	xbrli:stringItemType
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- Definition

Amount of advances from the Federal Home Loan Bank (FHLB).

+ References

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- Definition

Discloses the lowest interest rate applicable to any of the advances from the Federal Home Loan Bank, by branch, as of the Balance Sheet date.

+ 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 210.9-03.13(3)(a))

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

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- Definition

Discloses the highest interest rate applicable to any of the advances from the Federal Home Loan Bank, by branch, as of the Balance Sheet date.

+ References

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- Definition

Amount of advances or credit lines available from the Federal Home Loan Bank (FHLB).

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 470

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6479118&loc=d3e64650-112822

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.13(3)(a))

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

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22 (b))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 13

-Subparagraph 3(a)

-Article 9

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- Definition

Amount of the collateral pledged in support of federal home loan bank advances outstanding.

+ References

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- Definition

The percentage rate used to calculate dividend payments on preferred stock.

+ References

No definition available.

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FIRST CITIZENS BANCSHARES INC /TN/ 10-Q