Loans and Leases (Changes In Carrying Amount Of Accretable Yield) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2013	Dec. 31, 2012
Changes in Amount of Accretable Yield [Roll Forward]
Beginning balance	$ 539,564	$ 276,690
Accretion	(224,672)	(304,023)
Reclassifications from nonaccretable difference	92,349	353,708
Changes in expected cash flows that do not affect nonaccretable difference	32,749	213,189
Ending balance	$ 439,990	$ 539,564

Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield, Changes in Expected Cash Flows Not Affecting Nonaccretable Difference

No definition available.

+ Details

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Namespace Prefix:	fcnca_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of the excess of a loan's cash flows expected to be collected over the investor's initial investment in acquired loans not accounted for as debt securities with evidence of deterioration of credit quality.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 30

-Section 15

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=27045933&loc=d3e13503-111538

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 30

-Section 50

-Paragraph 2

-Subparagraph (a)(2)

-URI http://asc.fasb.org/extlink&oid=6379141&loc=d3e15032-111544

+ Details

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Period Type:	instant

- Definition

Amount of decrease from accretion of the excess of a loan's cash flows expected to be collected over the investor's initial investment in acquired loans not accounted for as debt securities with evidence of deterioration of credit quality.

+ References

+ Details

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- Details

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- Definition

Amount of increase of reclassification from nonaccretable difference to the excess of a loan's cash flows expected to be collected over the investor's initial investment in acquired loans not accounted for as debt securities with evidence of deterioration of credit quality.

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
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