Investment Securities (Detail) (USD $)	Sep. 30, 2012	Dec. 31, 2011
Investment [Line Items]
Amortized Cost	$ 120,679,000	$ 108,921,000
Gross Unrealized Gains	2,862,000	2,658,000
Gross Unrealized Losses	166,000	139,000
Fair Value	123,375,000	111,440,000
Amortized Cost	14,000	16,000
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	14,000	16,000
Agency mortgage-backed securities
Investment [Line Items]
Amortized Cost	22,022,000	11,689,000
Gross Unrealized Gains	538,000	542,000
Gross Unrealized Losses	9,000	11,000
Fair Value	22,551,000	12,220,000
Amortized Cost	14,000	16,000
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	14,000	16,000
Agency Collateralized Mortgage Obligations
Investment [Line Items]
Amortized Cost	24,278,000	23,196,000
Gross Unrealized Gains	169,000	152,000
Gross Unrealized Losses	90,000	60,000
Fair Value	24,357,000	23,288,000
Collateralized Mortgage Obligations Issued By Private Enterprise
Investment [Line Items]
Amortized Cost	666,000	896,000
Gross Unrealized Gains	19,000	16,000
Gross Unrealized Losses	28,000	32,000
Fair Value	657,000	880,000
Agency CMO
Investment [Line Items]
Amortized Cost	42,119,000	41,971,000
Gross Unrealized Gains	330,000	395,000
Gross Unrealized Losses	1,000	3,000
Fair Value	42,448,000	42,363,000
Municipal Notes
Investment [Line Items]
Amortized Cost	28,331,000	25,800,000
Gross Unrealized Gains	1,750,000	1,501,000
Gross Unrealized Losses	20,000	0
Fair Value	30,061,000	27,301,000
Debt Securities
Investment [Line Items]
Amortized Cost	117,416,000	103,552,000
Gross Unrealized Gains	2,806,000	2,606,000
Gross Unrealized Losses	148,000	106,000
Fair Value	120,074,000	106,052,000
Mutual Funds
Investment [Line Items]
Amortized Cost	3,263,000	5,369,000
Gross Unrealized Gains	56,000	52,000
Gross Unrealized Losses	18,000	33,000
Fair Value	$ 3,301,000	$ 5,388,000