XML 55 R44.htm IDEA: XBRL DOCUMENT v3.8.0.1
Securities - Additional Information (Detail)
$ in Thousands
3 Months Ended
Mar. 31, 2018
USD ($)
Security
Mar. 31, 2017
USD ($)
Dec. 31, 2017
USD ($)
Investments Debt And Equity Securities [Abstract]      
Proceeds from sales of securities $ 0 $ 0  
Gross realized gains 0 0  
Gross realized losses 0 $ 0  
Carrying value of pledged securities $ 127,808   $ 122,862
Number of securities in portfolio with unrealized losses | Security 122