Loans - Internal Risk Ratings (Detail) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
INTERNAL RISK RATING
Loan Receivables	$ 932,032	$ 902,345
Pass
INTERNAL RISK RATING
Loan Receivables	919,538	890,498
Special Mention
INTERNAL RISK RATING
Loan Receivables	1,176	2,260
Substandard
INTERNAL RISK RATING
Loan Receivables	11,318	9,587
Construction, Land and Land Development
INTERNAL RISK RATING
Loan Receivables	119,278	109,475
Construction, Land and Land Development | Pass
INTERNAL RISK RATING
Loan Receivables	117,219	107,306
Construction, Land and Land Development | Special Mention
INTERNAL RISK RATING
Loan Receivables		68
Construction, Land and Land Development | Substandard
INTERNAL RISK RATING
Loan Receivables	2,059	2,101
Commercial Mortgages (Non-Owner Occupied)
INTERNAL RISK RATING
Loan Receivables	193,480	180,074
Commercial Mortgages (Non-Owner Occupied) | Pass
INTERNAL RISK RATING
Loan Receivables	192,922	178,936
Commercial Mortgages (Non-Owner Occupied) | Substandard
INTERNAL RISK RATING
Loan Receivables	558	1,138
Commercial Mortgages (Owner Occupied)
INTERNAL RISK RATING
Loan Receivables	83,643	87,241
Commercial Mortgages (Owner Occupied) | Pass
INTERNAL RISK RATING
Loan Receivables	82,738	85,897
Commercial Mortgages (Owner Occupied) | Special Mention
INTERNAL RISK RATING
Loan Receivables	150	107
Commercial Mortgages (Owner Occupied) | Substandard
INTERNAL RISK RATING
Loan Receivables	755	1,237
Residential First Mortgages
INTERNAL RISK RATING
Loan Receivables	301,185	298,894
Residential First Mortgages | Pass
INTERNAL RISK RATING
Loan Receivables	297,409	295,372
Residential First Mortgages | Special Mention
INTERNAL RISK RATING
Loan Receivables	922	1,071
Residential First Mortgages | Substandard
INTERNAL RISK RATING
Loan Receivables	2,854	2,451
Residential Revolving and Junior Mortgages
INTERNAL RISK RATING
Loan Receivables	33,694	38,313
Residential Revolving and Junior Mortgages | Pass
INTERNAL RISK RATING
Loan Receivables	32,878	37,206
Residential Revolving and Junior Mortgages | Special Mention
INTERNAL RISK RATING
Loan Receivables	87
Residential Revolving and Junior Mortgages | Substandard
INTERNAL RISK RATING
Loan Receivables	729	1,107
Commercial and Industrial
INTERNAL RISK RATING
Loan Receivables	186,281	164,608
Commercial and Industrial | Pass
INTERNAL RISK RATING
Loan Receivables	182,195	162,392
Commercial and Industrial | Special Mention
INTERNAL RISK RATING
Loan Receivables	17	893
Commercial and Industrial | Substandard
INTERNAL RISK RATING
Loan Receivables	4,069	1,323
Consumer
INTERNAL RISK RATING
Loan Receivables	14,471	23,740
Consumer | Pass
INTERNAL RISK RATING
Loan Receivables	14,177	23,389
Consumer | Special Mention
INTERNAL RISK RATING
Loan Receivables		121
Consumer | Substandard
INTERNAL RISK RATING
Loan Receivables	$ 294	$ 230