Quarterly report pursuant to Section 13 or 15(d)

Regulatory Matters - Additional Information (Detail)

v2.4.0.6
Regulatory Matters - Additional Information (Detail) (USD $)
In Millions, unless otherwise specified
Sep. 30, 2012
Dec. 31, 2011
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]    
Minimum regulatory requirement ratio for total capital risk-weighted assets 8.00%  
Minimum ratio of Tier 1 capital to risk-weighted assets 4.00%  
Minimum ratio of qualifying total capital to risk-weighted assets for well capitalized 10.00%  
Minimum ratio of Tier 1 capital to average total assets for well capitalized 6.00%  
Daily average reserve balance required to be maintained with the FRB $ 0 $ 1.5
Bank Holding Companies [Member]
   
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]    
Leverage ratio 4.00%  
Depository Institutions [Member]
   
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]    
Leverage ratio 5.00%  
Minimum [Member]
   
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]    
Leverage ratio to rate banks 3.00%