Business Combinations - Rollforward of Acquired Non-Covered Loans (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013
Purchased Non Covered Loans [Line Items]
Balance, beginning of year	$ 25,493	$ 16,698
Accretion	22,188	42,208
Transfers to purchased non-covered other real estate owned	(4,160)
Balance, end of year	15,578	25,493
Non-Covered Loans [Member]
Purchased Non Covered Loans [Line Items]
Balance, beginning of year	448,753
Charge-offs, net of recoveries	(84)
Additions due to acquisitions	279,441	449,696
Accretion	9,745
Transfers to purchased non-covered other real estate owned	(4,160)
Transfer from covered loans due to loss share expiration	15,475
Payments received	(74,931)	(943)
Balance, end of year	$ 674,239	$ 448,753

Certain loans acquired in transfer accounted for as debt securities non covered loans due to loss share expiration.

No definition available.

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- Definition

Certain loans acquired in transfer not accounted for as debt securities accretable yield adjustment changes in expected cash flow.

+ References

No definition available.

+ Details

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- Definition

Non Covered Loans Transferred To Other Real Estate Owned.

+ References

No definition available.

+ Details

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- Details

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- Definition

Current period recognition due to accretion of the excess of a loan's cash flows expected to be collected over the investor's initial investment in the loan for loans accounted for as debt securities, with evidence of deterioration of credit quality since origination that were acquired by completion of a transfer for which it is probable, at acquisition, that the investor will be unable to collect all contractually required payments receivable.

+ 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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- Definition

Increases in the aggregate excess of a loan's cash flows expected to be collected over the investor's initial investment in the loan due to the acquisition of similar loans accounted for as debt securities during the period. This relates to loans accounted for as debt securities, with evidence of deterioration of credit quality since origination that were acquired by completion of a transfer for which it is probable, at acquisition, that the investor will be unable to collect all contractually required payments receivable.

+ References

+ Details

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- 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

+ Details

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- Definition

Amount of increase (decrease) 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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