Quarterly report pursuant to Section 13 or 15(d)

Accumulated Other Comprehensive Income - Additional Information (Detail)

v3.8.0.1
Accumulated Other Comprehensive Income - Additional Information (Detail) - USD ($)
$ in Thousands
3 Months Ended 9 Months Ended
Sep. 30, 2017
Sep. 30, 2016
Sep. 30, 2017
Sep. 30, 2016
Accumulated Other Comprehensive Income [Line Items]        
Net gain on sales of securities $ 267 $ 46 $ 1,473 $ 46
Net unrealized gains (losses) recorded in comprehensive income 227 321 971 314
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Net Unrealized Investment Gain (Loss) [Member]        
Accumulated Other Comprehensive Income [Line Items]        
Net gain on sales of securities $ 267 $ 46 $ 1,500 $ 46