Premises and Equipment - Additional Information (Detail) - USD ($) |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
|
| Property, Plant and Equipment [Abstract] | |||
| Depreciation expense for premises and equipment | $ 5,043,000 | $ 4,648,000 | $ 3,635,000 |