Summary of Loans by Portfolio Type and Internal Credit Quality Ratings (Detail) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Dec. 31, 2012	Jun. 30, 2012
Financing Receivable, Recorded Investment [Line Items]
Gross loans	$ 729,216	$ 730,599	$ 708,398
Increase (Decrease) in loan portfolios	(1,383)
Commercial loans
Financing Receivable, Recorded Investment [Line Items]
Gross loans	195,439	170,792	173,637
Consumer loans
Financing Receivable, Recorded Investment [Line Items]
Gross loans	27,106	27,296
Commercial real estate | Owner occupied
Financing Receivable, Recorded Investment [Line Items]
Gross loans	156,215	165,922
Commercial real estate | All other
Financing Receivable, Recorded Investment [Line Items]
Gross loans	158,179	150,189
Residential mortgage loans | Multi-family
Financing Receivable, Recorded Investment [Line Items]
Gross loans	97,383	105,119
Residential mortgage loans | Single-family
Financing Receivable, Recorded Investment [Line Items]
Gross loans	75,241	87,263
Land development loans
Financing Receivable, Recorded Investment [Line Items]
Gross loans	19,653	24,018
Pass
Financing Receivable, Recorded Investment [Line Items]
Gross loans	674,373	673,656
Increase (Decrease) in loan portfolios	717
Pass | Commercial loans
Financing Receivable, Recorded Investment [Line Items]
Gross loans	173,199	146,952
Increase (Decrease) in loan portfolios	26,247
Pass | Consumer loans
Financing Receivable, Recorded Investment [Line Items]
Gross loans	26,544	27,296
Increase (Decrease) in loan portfolios	(752)
Pass | Commercial real estate | Owner occupied
Financing Receivable, Recorded Investment [Line Items]
Gross loans	152,691	162,689
Increase (Decrease) in loan portfolios	(9,998)
Pass | Commercial real estate | All other
Financing Receivable, Recorded Investment [Line Items]
Gross loans	140,186	135,274
Increase (Decrease) in loan portfolios	4,912
Pass | Residential mortgage loans | Multi-family
Financing Receivable, Recorded Investment [Line Items]
Gross loans	97,383	104,747
Increase (Decrease) in loan portfolios	(7,364)
Pass | Residential mortgage loans | Single-family
Financing Receivable, Recorded Investment [Line Items]
Gross loans	73,264	84,237
Increase (Decrease) in loan portfolios	(10,973)
Pass | Land development loans
Financing Receivable, Recorded Investment [Line Items]
Gross loans	11,106	12,461
Increase (Decrease) in loan portfolios	(1,355)
Special Mention
Financing Receivable, Recorded Investment [Line Items]
Gross loans	5,302	15,804
Increase (Decrease) in loan portfolios	(10,502)
Special Mention | Commercial loans
Financing Receivable, Recorded Investment [Line Items]
Gross loans	217	2,381
Increase (Decrease) in loan portfolios	(2,164)
Special Mention | Consumer loans
Financing Receivable, Recorded Investment [Line Items]
Gross loans	562
Increase (Decrease) in loan portfolios	562
Special Mention | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Increase (Decrease) in loan portfolios	9,500
Special Mention | Commercial real estate | All other
Financing Receivable, Recorded Investment [Line Items]
Gross loans	4,523	3,859
Increase (Decrease) in loan portfolios	664
Special Mention | Residential mortgage loans | Multi-family
Financing Receivable, Recorded Investment [Line Items]
Gross loans		373
Increase (Decrease) in loan portfolios	(373)
Special Mention | Residential mortgage loans | Single-family
Financing Receivable, Recorded Investment [Line Items]
Gross loans		990
Increase (Decrease) in loan portfolios	(990)
Special Mention | Land development loans
Financing Receivable, Recorded Investment [Line Items]
Gross loans		8,201
Increase (Decrease) in loan portfolios	(8,201)
Substandard
Financing Receivable, Recorded Investment [Line Items]
Gross loans	48,565	41,027
Increase (Decrease) in loan portfolios	7,538
Substandard | Commercial loans
Financing Receivable, Recorded Investment [Line Items]
Gross loans	21,047	21,347
Increase (Decrease) in loan portfolios	(300)
Substandard | Commercial real estate | Owner occupied
Financing Receivable, Recorded Investment [Line Items]
Gross loans	3,523	3,232
Increase (Decrease) in loan portfolios	291
Substandard | Commercial real estate | All other
Financing Receivable, Recorded Investment [Line Items]
Gross loans	13,470	11,057
Increase (Decrease) in loan portfolios	2,413
Substandard | Residential mortgage loans | Single-family
Financing Receivable, Recorded Investment [Line Items]
Gross loans	1,978	2,036
Increase (Decrease) in loan portfolios	(58)
Substandard | Land development loans
Financing Receivable, Recorded Investment [Line Items]
Gross loans	8,547	3,355
Increase (Decrease) in loan portfolios	5,192
Doubtful
Financing Receivable, Recorded Investment [Line Items]
Gross loans	976	112
Increase (Decrease) in loan portfolios	864
Doubtful | Commercial loans
Financing Receivable, Recorded Investment [Line Items]
Gross loans	976	112
Increase (Decrease) in loan portfolios	864
Doubtful | Land development loans
Financing Receivable, Recorded Investment [Line Items]
Gross loans