Annual report pursuant to Section 13 and 15(d)

Premises and Equipment - Additional Information (Detail)

v2.4.1.9
Premises and Equipment - Additional Information (Detail) (USD $)
In Millions, unless otherwise specified
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Property Plant And Equipment Capitalized Interest Costs [Abstract]      
Depreciation and amortization expense $ 2.2us-gaap_DepreciationDepletionAndAmortization $ 1.9us-gaap_DepreciationDepletionAndAmortization $ 2.1us-gaap_DepreciationDepletionAndAmortization