Selected Quarterly Consolidated Financial Information (Unaudited) - Selected Quarterly Financial Data Consolidated Financial Statements (Parenthetical) (Detail) (USD $)
0 Months Ended 3 Months Ended 12 Months Ended
Jun. 08, 2012
Dec. 31, 2013
Sep. 30, 2013
Jun. 30, 2012
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2011
Quarterly Financial Information Disclosure [Abstract]              
Gain on sale of investment in affiliate bank $ 4,800,000     $ 4,800,000    $ 4,819,000   
Non-interest expense   1,500,000          
occupancy and equipment expenses     172,000        
marketing and advertising expenses     368,000        
professional services expenses     264,000        
foreclosed real estate expenses     349,000        
other general and administrative expenses     $ 268,000