Amortized Cost and Fair Value of Debt Securities by Contractual Maturity (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012
Amortized cost
Due in one year or less	$ 1,028
Due after one year through five years	7,490
Due after five years through ten years	17,022
Due after ten years	44,392
Available for sale Securities, Debt Maturities, with Single Maturity Date, Amortized Cost, Total	69,932
Mortgage-backed securities and CMO	46,004
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Total	115,936
Fair Value
Due in one year or less	1,032
Due after one year through five years	7,644
Due after five years through ten years	17,455
Due after ten years	45,766
Available for sale Securities, Debt Maturities, with Single Maturity Date, Fair Value, Total	71,897
Mortgage-backed securities and CMO	46,608
Available-for-sale Securities, Debt Securities, Total	118,505
Amortized cost
Due in one year or less	0
Due after one year through five years	0
Due after five years through ten years
Due after ten years	0
Held-to-maturity Securities, Debt Maturities, with Single Maturity Date, Net Carrying Amount, Total	0
Mortgage-backed securities and CMO	14
Held-to-maturity Securities, Debt Maturities, Net Carrying Amount, Total	14
Fair Value
Due in one year or less	0
Due after one year through five years	0
Due after five years through ten years
Due after ten years	0
Held-to-maturity Securities, Debt Maturities, with Single Maturity Date, Fair Value, Total	0
Mortgage-backed securities and CMO	14
Held-to-maturity Securities, Debt Maturities, Fair Value, Total	$ 14