Fair Values of Financial Instruments - Carrying Amount, Estimated Fair Value and Level Within Fair Value Hierarchy of Financial Instruments (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
Financial assets
Securities available for sale	$ 131,178,000	$ 138,314,000
Carrying Amount [Member]
Financial assets
Securities available for sale	131,178,000	138,314,000
Federal Home Loan Bank stock	11,961,000	11,961,000
Carrying Amount [Member] | Level 1 [Member]
Financial assets
Cash	1,464,000	1,576,000
Carrying Amount [Member] | Level 2 [Member]
Financial assets
Cash equivalents	145,501,000	134,427,000
Bank owned life insurance	51,377,000	50,048,000
Accrued interest receivable	3,649,000	3,874,000
Financial liabilities
Deposits	1,118,911,000	1,135,204,000
Securities sold under agreements to repurchase	69,305,000	64,765,000
Federal Home Loan Bank advances	45,000,000	35,000,000
Subordinated debentures	32,990,000	32,990,000
Accrued interest payable	2,041,000	2,314,000
Carrying Amount [Member] | Level 3 [Member]
Financial assets
Loans, net	1,030,422,000	1,012,512,000
Carrying Amount [Member] | Interest rate swap agreement [Member]
Financial liabilities
Interest rate swap	264,000	1,113,000
Fair Value [Member]
Financial assets
Securities available for sale	131,178,000	138,314,000
Federal Home Loan Bank stock	11,961,000	11,961,000
Fair Value [Member] | Level 1 [Member]
Financial assets
Cash	1,464,000	1,576,000
Fair Value [Member] | Level 2 [Member]
Financial assets
Cash equivalents	145,501,000	134,427,000
Bank owned life insurance	51,377,000	50,048,000
Accrued interest receivable	3,649,000	3,874,000
Financial liabilities
Deposits	1,120,576,000	1,135,614,000
Securities sold under agreements to repurchase	69,305,000	64,765,000
Federal Home Loan Bank advances	45,139,000	35,000,000
Subordinated debentures	32,974,000	32,943,000
Accrued interest payable	2,041,000	2,314,000
Fair Value [Member] | Level 3 [Member]
Financial assets
Loans, net	1,027,300,000	1,004,541,000
Fair Value [Member] | Interest rate swap agreement [Member]
Financial liabilities
Interest rate swap	$ 264,000	$ 1,113,000