The valuation allowance for financing receivables that are expected to be uncollectible that were collectively evaluated for impairment.

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Amount of valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment.

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The balance of financing receivables that were collectively evaluated for impairment.

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The balance of financing receivables that were individually evaluated for impairment.

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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.

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Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements.

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Loans - Allowances for Loan Losses and Ending Balances by Portfolio Class and Based on Impairment Method (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually evaluated for impairment	$ 66		$ 244
Collectively evaluated for impairment	5,852		5,360
Total ending allowance balance	5,918	$ 5,633	5,604	$ 6,289	$ 5,454	$ 5,291
Loans:
Loans individually evaluated for impairment	5,928		7,882
Loans collectively evaluated for impairment	528,933		508,418
Total ending loans balance	534,861		516,300
Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually evaluated for impairment	4		74
Collectively evaluated for impairment	1,845		1,739
Total ending allowance balance	1,849	1,884	1,813	2,362	1,704	2,207
Loans:
Loans individually evaluated for impairment	1,096		1,726
Loans collectively evaluated for impairment	140,923		138,547
Total ending loans balance	142,019		140,273
Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually evaluated for impairment	46		151
Collectively evaluated for impairment	1,566		1,584
Total ending allowance balance	1,612	1,699	1,735	1,718	1,538	1,264
Loans:
Loans individually evaluated for impairment	3,458		4,686
Loans collectively evaluated for impairment	178,576		174,977
Total ending loans balance	182,034		179,663
Residential Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually evaluated for impairment	16		19
Collectively evaluated for impairment	1,220		1,254
Total ending allowance balance	1,236	1,196	1,273	1,264	1,303	1,189
Loans:
Loans individually evaluated for impairment	1,374		1,470
Loans collectively evaluated for impairment	160,810		155,702
Total ending loans balance	162,184		157,172
Construction & Land Development [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Collectively evaluated for impairment	279		237
Total ending allowance balance	279	244	237	222	184	178
Loans:
Loans collectively evaluated for impairment	30,706		22,886
Total ending loans balance	30,706		22,886
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Collectively evaluated for impairment	259		175
Total ending allowance balance	259	188	175	182	165	141
Loans:
Loans collectively evaluated for impairment	17,918		16,306
Total ending loans balance	17,918		16,306
Unallocated [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Collectively evaluated for impairment	683		371
Total ending allowance balance	$ 683	$ 422	$ 371	$ 541	$ 560	$ 312