Loans - Summary of Gross Loans and Commercial Loans (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2012
Financing Receivable, Recorded Investment, Past Due [Line Items]
Percentage of loans and leases receivable gross carrying amount	100.00%	100.00%
Total loans	$ 731,540	$ 739,058
Less: other loans held for sale	(776)	(776)
Loans, gross	730,764	738,282	761,687
Commercial real estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Percentage of loans and leases receivable gross carrying amount	62.40%	62.10%
Total loans	456,786	459,212
Single-family residential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Percentage of loans and leases receivable gross carrying amount	22.80%	22.80%
Total loans	166,389	168,180
Commercial and industrial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Percentage of loans and leases receivable gross carrying amount	6.80%	7.00%
Total loans	49,620	51,661
Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Percentage of loans and leases receivable gross carrying amount	6.70%	6.80%
Total loans	49,051	50,574
Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Percentage of loans and leases receivable gross carrying amount	1.30%	1.30%
Total loans	9,694	9,431
Loans, gross	$ 9,694	$ 9,431