XML 73 R57.htm IDEA: XBRL DOCUMENT v3.3.1.900
Investment Securities - Additional Information (Detail)
12 Months Ended
Dec. 31, 2015
USD ($)
Security
Dec. 31, 2014
USD ($)
Security
Investments Debt And Equity Securities [Abstract]    
Number of debt securities continues loss position for more than twelve months | Security 13 10
Number of debt securities continues loss position for less than twelve months | Security 102 31
Investment securities available-for-sale carrying amount $ 61,300,000 $ 61,100,000
Gains realized on sales of securities available-for-sale 462,000 104,000
Losses on sales of securities $ 0 $ 0