Subsequent Events (Detail)	Jun. 30, 2012
Subsequent Event [Line Items]
Tier 1 capital	12.31%
Total risk-based capital	16.24%
Tier I leverage (to average assets)	11.39%
Pro-Forma Capital Ratios
Subsequent Event [Line Items]
Tier 1 capital	10.95%
Total risk-based capital	14.89%
Tier I leverage (to average assets)	10.14%