Segment Reporting - Summary of Results for Reportable Segments (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Segment Reporting Information [Line Items]
Net interest income	$ 6,707us-gaap_InterestIncomeExpenseNet	$ 7,201us-gaap_InterestIncomeExpenseNet
Provision (reduction in reserve) for loan losses	(166)	414
Total non-interest income	1,291us-gaap_NoninterestIncome	1,147us-gaap_NoninterestIncome
Total non-interest expense	6,977us-gaap_NoninterestExpense	6,884us-gaap_NoninterestExpense
Income before income taxes	1,187	1,050
Provision for income taxes	351us-gaap_IncomeTaxExpenseBenefit	276us-gaap_IncomeTaxExpenseBenefit
Net income	836us-gaap_ProfitLoss	774us-gaap_ProfitLoss
Other significant items:
Total assets	564,882us-gaap_Assets	575,716us-gaap_Assets	572,609us-gaap_Assets
Total investment securities	249,864us-gaap_MarketableSecurities	189,906us-gaap_MarketableSecurities
Total loans, net	239,218	276,717	259,516
Investment in subsidiaries	5	5
Fixed asset addition	1,403	721
Depreciation and amortization expense	213us-gaap_DepreciationAndAmortization	180us-gaap_DepreciationAndAmortization
Total interest income from external customers	7,321	7,846
Eliminations [Member]
Segment Reporting Information [Line Items]
Total non-interest income	(1,191)	(1,113)
Total non-interest expense	(153)	(210)
Income before income taxes	(1,038)	(903)
Net income	(1,038)	(903)
Other significant items:
Total assets	(159,735)	(148,228)
Total loans, net	(63,346)	(56,721)
Investment in subsidiaries	(76,865)	(73,195)
Total interest income from affiliates	(884)	(768)
FUSB [Member]
Segment Reporting Information [Line Items]
Provision (reduction in reserve) for loan losses	(525)		(1,920)
Other significant items:
Total loans, net	168,431		187,500
FUSB [Member] \| Operating Segments [Member]
Segment Reporting Information [Line Items]
Net interest income	3,844	4,087
Provision (reduction in reserve) for loan losses	(525)	(175)
Total non-interest income	1,149	931
Total non-interest expense	4,281	4,330
Income before income taxes	1,237	863
Provision for income taxes	370	176
Net income	867	687
Other significant items:
Total assets	567,318	577,804
Total investment securities	249,784	189,826
Total loans, net	231,778	268,000
Investment in subsidiaries	5	784
Fixed asset addition	1,241	708
Depreciation and amortization expense	153	128
Total interest income from external customers	3,578	3,969
Total interest income from affiliates	882	765
ALC [Member]
Segment Reporting Information [Line Items]
Provision (reduction in reserve) for loan losses	358		1,846
Other significant items:
Total loans, net	70,787		72,016
ALC [Member] \| Operating Segments [Member]
Segment Reporting Information [Line Items]
Net interest income	2,861	3,112
Provision (reduction in reserve) for loan losses	359	589
Total non-interest income	220	286
Total non-interest expense	2,493	2,556
Income before income taxes	229	253
Provision for income taxes	86	99
Net income	143	154
Other significant items:
Total assets	75,124	68,625
Total loans, net	70,786	65,438
Fixed asset addition	162	13
Depreciation and amortization expense	60	52
Total interest income from external customers	3,743	3,877
All Other [Member] \| Operating Segments [Member]
Segment Reporting Information [Line Items]
Net interest income	2	2
Total non-interest income	1,113	1,043
Total non-interest expense	356	208
Income before income taxes	759	837
Provision for income taxes	(105)	1
Net income	864	836
Other significant items:
Total assets	82,175	77,515
Total investment securities	80	80
Investment in subsidiaries	76,865	72,416
Total interest income from affiliates	$ 2	$ 3

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Provision reduction in reserve for loan losses.

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