Long-Term Obligations (Details) (USD $)	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013
Long-term Debt, Fiscal Year Maturity [Abstract]
2014	147,000
2015	0
2016	10,725,000
2017	136,104,000
2018	0
Thereafter	204,344,000
Total long-term obligations	351,320,000us-gaap_LongTermDebt	510,769,000us-gaap_LongTermDebt
Trust Preferred Securities	128,500,000fcnca_TrustPreferredSecurities
Junior Subordinated Debt [Member]
Long-term Debt, Fiscal Year Maturity [Abstract]
Total long-term obligations	132,939,000
Junior Subordinated Debt [Member] \| Junior Subordinanted Debenture at 3 Month Libor Plus 1.75% Maturing June 30, 2036 [Member]
Long-term Debt, Fiscal Year Maturity [Abstract]
Total long-term obligations	96,392,000	96,392,000
Junior Subordinated Debt [Member] \| Junior Subordinanted Debenture at 3 Month Libor Plus 1.75% Maturing June 30, 2036 [Member] \| 3-month LIBOR [Member]
Debt Instrument [Line Items]
Description of variable rate basis	3-month LIBOR
Basis spread on variable rate	1.75%
Junior Subordinated Debt [Member] \| Junior Subordinated Debenture At 3 Month Libor Plus 2 Point 25 Percent Maturing June 15 2034 [Member] [Member]
Long-term Debt, Fiscal Year Maturity [Abstract]
Total long-term obligations	26,547,000	0
Junior Subordinated Debt [Member] \| Junior Subordinated Debenture At 3 Month Libor Plus 2 Point 25 Percent Maturing June 15 2034 [Member] [Member] \| 3-month LIBOR [Member]
Debt Instrument [Line Items]
Description of variable rate basis	3-month LIBOR
Basis spread on variable rate	2.25%
Junior Subordinated Debt [Member] \| Junior Subordinated Debenture At 3 Month Libor Plus 2 Point 85 Percent Maturing April 7 2034 [Member] [Member]
Long-term Debt, Fiscal Year Maturity [Abstract]
Total long-term obligations	10,000,000	0
Junior Subordinated Debt [Member] \| Junior Subordinated Debenture At 3 Month Libor Plus 2 Point 85 Percent Maturing April 7 2034 [Member] [Member] \| 3-month LIBOR [Member]
Debt Instrument [Line Items]
Description of variable rate basis	3-month LIBOR
Basis spread on variable rate	2.85%
Subordinated Debt [Member] \| Subordinated Notes Payable At 5 Point 125 Percent Maturing June 1 2015 [Member]
Debt Instrument [Line Items]
Debt interest rate	5.125%
Long-term Debt, Fiscal Year Maturity [Abstract]
Total long-term obligations	0	125,000,000
Subordinated Debt [Member] \| Subordinated Notes Payable at 5.125% Maturing June 1, 2015 [Member]
Debt Instrument [Line Items]
Debt interest rate	8.00%
Long-term Debt, Fiscal Year Maturity [Abstract]
Total long-term obligations	15,000,000	0
Capital Lease Obligations [Member]
Long-term Debt, Fiscal Year Maturity [Abstract]
Total long-term obligations	3,150,000	6,515,000
Federal Home Loan Bank Advances [Member] \| Rates Ranging from 2.00% to 3.88% and Maturing Through September 2018 [Member]
Long-term Debt, Fiscal Year Maturity [Abstract]
Total long-term obligations	160,268,000	240,283,000
Federal Home Loan Bank Advances [Member] \| Rates Ranging from 2.00% to 3.88% and Maturing Through September 2018 [Member] \| Minimum
Debt Instrument [Line Items]
Debt interest rate	2.00%
Federal Home Loan Bank Advances [Member] \| Rates Ranging from 2.00% to 3.88% and Maturing Through September 2018 [Member] \| Maximum
Debt Instrument [Line Items]
Debt interest rate	3.58%
Federal Home Loan Bank Advances [Member] \| Rates Ranging from 4.74% and Maturity of July 2017 [Member]
Debt Instrument [Line Items]
Debt interest rate	4.74%
Long-term Debt, Fiscal Year Maturity [Abstract]
Total long-term obligations	10,000,000	10,000,000
Unamortized Acquisition Accounting Adjustments [Member]
Long-term Debt, Fiscal Year Maturity [Abstract]
Total long-term obligations	(156,000)	2,449,000
Other Long Term Debt [Member]
Long-term Debt, Fiscal Year Maturity [Abstract]
Total long-term obligations	30,119,000	$ 30,130,000

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

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Contractual interest rate for funds borrowed, under the debt agreement.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

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Carrying amount of long-term debt, net of unamortized discount or premium, including current and noncurrent amounts. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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

-Publisher SEC

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

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing after the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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