v2.4.0.6
Amortized Cost Unrecognized Gains and Losses and Fair Value of Securities Held to Maturity (Detail) (USD $)
In Thousands, unless otherwise specified
Jun. 30, 2012
Dec. 31, 2011
Schedule of Held-to-maturity Securities [Line Items]  
Amortized Cost$ 54,882$ 48,975
US States and Political Subdivisions Debt Securities
  
Schedule of Held-to-maturity Securities [Line Items]  
Amortized Cost54,88248,975
Gross Unrecognized Gains1,9211,693
Gross Unrecognized Losses(57)(25)
Fair Value$ 56,746$ 50,643