Business Combinations - Schedule of Changes in Accretable Discounts Related Acquired Non-Covered Loans (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013
Schedule Of Covered Loans Acquired Accretable Discounts [Line Items]
Balance, beginning of year	$ 25,493	$ 16,698
Accretion	(22,188)	(42,208)
Transfers between non-accretable and accretable discounts, net	12,273	51,003
Balance, end of year	15,578	25,493
Non-Covered Loans [Member]
Schedule Of Covered Loans Acquired Accretable Discounts [Line Items]
Balance, beginning of year	448,753
Additions due to acquisitions	279,441	449,696
Accretion	(9,745)
Balance, end of year	674,239	448,753
Non-Covered Loans [Member] \| Discount Accretion [Member]
Schedule Of Covered Loans Acquired Accretable Discounts [Line Items]
Balance, beginning of year	26,189
Additions due to acquisitions	7,799	26,189
Accretion	(9,745)
Transfers between non-accretable and accretable discounts, net	1,473
Balance, end of year	$ 25,716	$ 26,189

Certain loans acquired in transfer accounted for as debt securities non accretable and accretable discounts net.

No definition available.

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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

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