Loans and Allowance for Loan Losses - Summary of Activity in the Loan Balances and the Allowance for Loan Losses by Segment (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance, beginning of period				$ 17,637				$ 17,063	$ 17,637	$ 17,063	$ 16,136
Losses charged off									(6,019)	(7,578)	(10,109)
Recoveries									1,512	910	683
Provision for loan losses	1,025	950	1,050	1,350	1,800	1,875	1,667	1,900	4,375	7,242	10,353
Balance, end of period	17,505				17,637				17,505	17,637	17,063
Ending allowance balance attributable to loans:
Individually evaluated for impairment	938				1,673				938	1,673	3,932
Collectively evaluated for impairment	16,567				15,964				16,567	15,964	13,131
Total ending allowance balance	17,505				17,637				17,505	17,637	17,063
Loans:
Individually evaluated for impairment	21,511				26,167				21,511	26,167	33,592
Collectively evaluated for impairment	880,788				856,381				880,788	856,381	809,496
Total ending loans balance	902,299				882,548				902,299	882,548	843,088
Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance, beginning of period				11,386				10,714	11,386	10,714	11,127
Losses charged off									(2,325)	(3,199)	(5,195)
Recoveries									697	388	280
Provision for loan losses									364	3,483	4,502
Balance, end of period	10,122				11,386				10,122	11,386	10,714
Ending allowance balance attributable to loans:
Individually evaluated for impairment	865				1,449				865	1,449	3,747
Collectively evaluated for impairment	9,257				9,937				9,257	9,937	6,967
Total ending allowance balance	10,122				11,386				10,122	11,386	10,714
Loans:
Individually evaluated for impairment	17,842				23,321				17,842	23,321	31,746
Collectively evaluated for impairment	383,749				390,684				383,749	390,684	350,106
Total ending loans balance	401,591				414,005				401,591	414,005	381,852
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance, beginning of period				835				1,409	835	1,409	1,317
Losses charged off									(121)	(213)	(262)
Recoveries									8	45	42
Provision for loan losses									(225)	(406)	312
Balance, end of period	497				835				497	835	1,409
Ending allowance balance attributable to loans:
Individually evaluated for impairment	73				209				73	209	148
Collectively evaluated for impairment	424				626				424	626	1,261
Total ending allowance balance	497				835				497	835	1,409
Loans:
Individually evaluated for impairment	472				597				472	597	705
Collectively evaluated for impairment	88,174				68,108				88,174	68,108	75,865
Total ending loans balance	88,646				68,705				88,646	68,705	76,570
Residential Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance, beginning of period				1,559				1,331	1,559	1,331	805
Losses charged off									(754)	(1,430)	(1,664)
Recoveries									350	96	22
Provision for loan losses									256	1,562	2,168
Balance, end of period	1,411				1,559				1,411	1,559	1,331
Ending allowance balance attributable to loans:
Individually evaluated for impairment	0				15				0	15	37
Collectively evaluated for impairment	1,411				1,544				1,411	1,544	1,294
Total ending allowance balance	1,411				1,559				1,411	1,559	1,331
Loans:
Individually evaluated for impairment	1,731				1,790				1,731	1,790	1,141
Collectively evaluated for impairment	64,776				63,193				64,776	63,193	63,383
Total ending loans balance	66,507				64,983				66,507	64,983	64,524
Home Equity Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance, beginning of period				2,357				2,289	2,357	2,289	1,512
Losses charged off									(1,775)	(1,372)	(1,895)
Recoveries									66	35	62
Provision for loan losses									2,836	1,405	2,610
Balance, end of period	3,484				2,357				3,484	2,357	2,289
Ending allowance balance attributable to loans:
Individually evaluated for impairment	0				0				0	0	0
Collectively evaluated for impairment	3,484				2,357				3,484	2,357	2,289
Total ending allowance balance	3,484				2,357				3,484	2,357	2,289
Loans:
Individually evaluated for impairment	1,111				398				1,111	398	0
Collectively evaluated for impairment	121,965				122,432				121,965	122,432	126,958
Total ending loans balance	123,076				122,830				123,076	122,830	126,958
Indirect
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance, beginning of period				1,230				891	1,230	891	904
Losses charged off									(678)	(963)	(695)
Recoveries									335	288	209
Provision for loan losses									706	1,014	473
Balance, end of period	1,593				1,230				1,593	1,230	891
Ending allowance balance attributable to loans:
Individually evaluated for impairment	0				0				0	0	0
Collectively evaluated for impairment	1,593				1,230				1,593	1,230	891
Total ending allowance balance	1,593				1,230				1,593	1,230	891
Loans:
Individually evaluated for impairment	195				0				195	0	0
Collectively evaluated for impairment	206,128				199,924				206,128	199,924	180,089
Total ending loans balance	206,323				199,924				206,323	199,924	180,089
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance, beginning of period				270				429	270	429	471
Losses charged off									(366)	(401)	(398)
Recoveries									56	58	68
Provision for loan losses									438	184	288
Balance, end of period	398				270				398	270	429
Ending allowance balance attributable to loans:
Individually evaluated for impairment	0				0				0	0	0
Collectively evaluated for impairment	398				270				398	270	429
Total ending allowance balance	398				270				398	270	429
Loans:
Individually evaluated for impairment	160				61				160	61	0
Collectively evaluated for impairment	15,996				12,040				15,996	12,040	13,095
Total ending loans balance	$ 16,156				$ 12,101				$ 16,156	$ 12,101	$ 13,095