Allowance for Loan Losses, by Loan Segment (Detail) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2016	Mar. 31, 2015
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	$ 20,233	$ 20,227
(Recovery of) provision for loan losses	1,196	1,146
Benefit attributable to the FDIC indemnification asset	(9)	(46)
(Recovery of) provision for loan losses charged to operations	1,187	1,100
(Recovery of) provision for loan losses recorded through the FDIC indemnification asset	9	46
Charge-offs	(1,141)	(1,578)
Recoveries	179	457
Net (charge-offs) recoveries	(962)	(1,121)
Ending balance	20,467	20,252
Commercial Loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	13,133	13,047
(Recovery of) provision for loan losses	308	613
Benefit attributable to the FDIC indemnification asset		29
(Recovery of) provision for loan losses charged to operations	308	642
(Recovery of) provision for loan losses recorded through the FDIC indemnification asset		(29)
Charge-offs	(284)	(681)
Recoveries	113	75
Net (charge-offs) recoveries	(171)	(606)
Ending balance	13,270	13,054
Consumer Real Estate
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	6,410	6,510
(Recovery of) provision for loan losses	744	308
Benefit attributable to the FDIC indemnification asset	(9)	(75)
(Recovery of) provision for loan losses charged to operations	735	233
(Recovery of) provision for loan losses recorded through the FDIC indemnification asset	9	75
Charge-offs	(690)	(402)
Recoveries	30	144
Net (charge-offs) recoveries	(660)	(258)
Ending balance	6,494	6,560
Consumer and Other
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	690	670
(Recovery of) provision for loan losses	144	225
(Recovery of) provision for loan losses charged to operations	144	225
Charge-offs	(254)	(495)
Recoveries	123	238
Net (charge-offs) recoveries	(131)	(257)
Ending balance	703	638
Allowance Excluding Purchased Credit Impaired
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	20,179	20,169
(Recovery of) provision for loan losses	1,226	1,090
Charge-offs	(1,141)	(1,578)
Recoveries	179	457
Net (charge-offs) recoveries	(962)	(1,121)
Ending balance	20,443	20,138
Allowance Excluding Purchased Credit Impaired \| Commercial Loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	13,133	13,010
(Recovery of) provision for loan losses	308	650
Charge-offs	(284)	(681)
Recoveries	113	75
Net (charge-offs) recoveries	(171)	(606)
Ending balance	13,270	13,054
Allowance Excluding Purchased Credit Impaired \| Consumer Real Estate
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	6,356	6,489
(Recovery of) provision for loan losses	774	215
Charge-offs	(690)	(402)
Recoveries	30	144
Net (charge-offs) recoveries	(660)	(258)
Ending balance	6,470	6,446
Allowance Excluding Purchased Credit Impaired \| Consumer and Other
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	690	670
(Recovery of) provision for loan losses	144	225
Charge-offs	(254)	(495)
Recoveries	123	238
Net (charge-offs) recoveries	(131)	(257)
Ending balance	703	638
Purchased Credit Impaired
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	54	58
(Recovery of) provision for loan losses	(30)	56
Benefit attributable to the FDIC indemnification asset	(9)	(46)
(Recovery of) provision for loan losses charged to operations	(39)	10
(Recovery of) provision for loan losses recorded through the FDIC indemnification asset	9	46
Ending balance	24	114
Purchased Credit Impaired \| Commercial Loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance		37
(Recovery of) provision for loan losses		(37)
Benefit attributable to the FDIC indemnification asset		29
(Recovery of) provision for loan losses charged to operations		(8)
(Recovery of) provision for loan losses recorded through the FDIC indemnification asset		(29)
Purchased Credit Impaired \| Consumer Real Estate
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	54	21
(Recovery of) provision for loan losses	(30)	93
Benefit attributable to the FDIC indemnification asset	(9)	(75)
(Recovery of) provision for loan losses charged to operations	(39)	18
(Recovery of) provision for loan losses recorded through the FDIC indemnification asset	9	75
Ending balance	$ 24	$ 114

Allowance for Loan and Lease Loss, Recovery of (Provision for) Bad Debts

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Allowance for (Recovery of) provision for Loan and Lease Losses

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(Provision) Benefit for Loan Losses

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Provision for (Recovery of) Loan and Lease Losses

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Provision For (Recovery) of Loan Losses Recorded Through FDIC Indemnification Asset

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Amount of loans and leases that have been written off from both loan receivables and allowance reserve for credit loss.

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Amount, after recoveries, of loans and leases that have been written-off.

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Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=49124121&loc=SL6953423-111524

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=49124121&loc=SL6953423-111524

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.7(d))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (b)(1)(ii)
-URI http://asc.fasb.org/extlink&oid=6379141&loc=d3e15032-111544

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
-Number Topic 6
-Section L
-Subsection 1

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