Loans and Allowance for Loan and Lease Losses - Troubled Debt Restructurings (Detail) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2015 USD ($) Loan	Jun. 30, 2014 USD ($) Loan	Jun. 30, 2015 USD ($) Loan	Jun. 30, 2014 USD ($) Loan
Financing Receivable, Modifications [Line Items]
Number of loans \| Loan	4	1	4	1
Pre-Modification Outstanding Recorded Investment	$ 7,243	$ 300	$ 7,243	$ 300
Post Modification Outstanding Recorded Investment	$ 7,243	$ 193	$ 7,243	$ 193
Performing [Member]
Financing Receivable, Modifications [Line Items]
Number of loans \| Loan	3	0	3	0
Pre-Modification Outstanding Recorded Investment	$ 6,993	$ 0	$ 6,993	$ 0
Post Modification Outstanding Recorded Investment	$ 6,993	$ 0	$ 6,993	$ 0
Performing [Member] \| Commercial loans [Member]
Financing Receivable, Modifications [Line Items]
Number of loans \| Loan	1	0	1	0
Pre-Modification Outstanding Recorded Investment	$ 94	$ 0	$ 94	$ 0
Post Modification Outstanding Recorded Investment	$ 94	$ 0	$ 94	$ 0
Performing [Member] \| Owner occupied [Member] \| Commercial real estate [Member]
Financing Receivable, Modifications [Line Items]
Number of loans \| Loan	1	0	1	0
Pre-Modification Outstanding Recorded Investment	$ 2,741	$ 0	$ 2,741	$ 0
Post Modification Outstanding Recorded Investment	$ 2,741	$ 0	$ 2,741	$ 0
Performing [Member] \| All other [Member] \| Commercial real estate [Member]
Financing Receivable, Modifications [Line Items]
Number of loans \| Loan	1	0	1	0
Pre-Modification Outstanding Recorded Investment	$ 4,158	$ 0	$ 4,158	$ 0
Post Modification Outstanding Recorded Investment	$ 4,158	$ 0	$ 4,158	$ 0
Nonperforming [Member]
Financing Receivable, Modifications [Line Items]
Number of loans \| Loan	1	1	1	1
Pre-Modification Outstanding Recorded Investment	$ 250	$ 300	$ 250	$ 300
Post Modification Outstanding Recorded Investment	$ 250	$ 193	$ 250	$ 193
Nonperforming [Member] \| Commercial loans [Member]
Financing Receivable, Modifications [Line Items]
Number of loans \| Loan	1	1	1	1
Pre-Modification Outstanding Recorded Investment	$ 250	$ 300	$ 250	$ 300
Post Modification Outstanding Recorded Investment	$ 250	$ 193	$ 250	$ 193

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Number of financing receivables that have been modified by troubled debt restructurings.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 33

-URI http://asc.fasb.org/extlink&oid=35738203&loc=SL6953676-111524

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