Business Combination - Summary of Estimated Fair Values of Assets Acquired and Liabilities Assumed at Date of Acquisition (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Jul. 31, 2015
Assets acquired:
Goodwill	$ 1,845
Colonial American Bank [Member]
Assets acquired:
Securities		$ 6,758
Loans		121,196
Other real estate owned		257
Deferred tax asset - recognition of net operating loss carryforward		2,292
Deferred tax asset - relating to purchase accounting adjustments		952
Other assets		8,823
Core deposit intangible		277
Goodwill		1,845
Total assets acquired		142,400
Liabilities assumed:
Deposits		123,346
Federal Home Loan Bank advances		6,800
Other liabilities		309
Total liabilities assumed		130,455
Net assets acquired		11,945
Colonial American Bank [Member] | Book Value [Member]
Assets acquired:
Securities		6,758
Loans		125,063
Allowance for loan losses		(1,578)
Other real estate owned		405
Other assets		8,823
Total assets acquired		139,471
Liabilities assumed:
Deposits		123,103
Federal Home Loan Bank advances		6,800
Other liabilities		309
Total liabilities assumed		130,212
Net assets acquired		9,259
Colonial American Bank [Member] | Purchase Accounting Adjustments [Member]
Assets acquired:
Loans		(3,867)
Allowance for loan losses		1,578
Other real estate owned		(148)
Deferred tax asset - recognition of net operating loss carryforward		2,292
Deferred tax asset - relating to purchase accounting adjustments		952
Core deposit intangible		277
Goodwill		1,845
Total assets acquired		2,929
Liabilities assumed:
Deposits		243
Total liabilities assumed		243
Net assets acquired		$ 2,686