Other Borrowings - Summary of Other Borrowings (Parenthetical) (Detail)	3 Months Ended	12 Months Ended
Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Daily Rate Credit From Federal Home Loan Bank [Member]
Federal Home Loan Bank Borrowings By Year Of Maturity And Applicable Interest Rate [Line Items]
Debt instrument effective rate		0.36%	0.36%
Revolving Credit Facility 1 [Member]
Federal Home Loan Bank Borrowings By Year Of Maturity And Applicable Interest Rate [Line Items]
Interest rate description	90-day LIBOR plus 3.50% (3.73% at March 31, 2015 and December 31, 2014)
Interest rate, margin to be added	3.50%		3.50%
Debt instrument effective rate	3.73%		3.73%
Debt instrument, maturity period	2016-08		2016-08
Revolving Credit Facility [Member]
Federal Home Loan Bank Borrowings By Year Of Maturity And Applicable Interest Rate [Line Items]
Interest rate description	90-day LIBOR plus 4.00% (4.24% at March 31, 2014)
Interest rate, margin to be added		4.00%
Debt instrument effective rate		4.24%
Debt instrument, maturity period		2016-08
Correspondent Bank Advances [Member]
Federal Home Loan Bank Borrowings By Year Of Maturity And Applicable Interest Rate [Line Items]
Debt instrument effective rate	4.50%	4.50%	4.50%
Maturity period of advances	Nov. 27, 2017	Nov. 27, 2017	Nov. 27, 2017
Subordinated Debt One [Member]
Federal Home Loan Bank Borrowings By Year Of Maturity And Applicable Interest Rate [Line Items]
Interest rate description	90-day LIBOR plus 1.60% (1.84% at March 31, 2014)
Interest rate, margin to be added		1.60%
Debt instrument effective rate		1.84%
Debt instrument, maturity period		2016-06
Subordinated Debt Two [Member]
Federal Home Loan Bank Borrowings By Year Of Maturity And Applicable Interest Rate [Line Items]
Interest rate description	90-day LIBOR plus 1.75% (2.02% at March 31, 2015, 1.99% at December 31, 2014 and 1.98% at March 31, 2014)
Interest rate, margin to be added	1.75%	1.75%	1.75%
Debt instrument effective rate	2.02%	1.98%	1.99%
Debt instrument, maturity period	2016-09	2016-09	2016-09

Debt instrument maturities month year.

No definition available.

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- 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.

+ Details

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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.

+ Details

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- Definition

Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 835

-SubTopic 30

-Section 45

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28551-108399

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 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22(a)(1))

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

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- Definition

Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

Reference 2: 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(a)(2))

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

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