Other Income and Expenses - Other Expenses (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Other Income and Expenses [Abstract]
Advertising	$ 552	$ 596	$ 489
Data processing	1,339	1,254	1,434
FDIC and state banking assessments	1,033	870	503
Legal and accounting	493	535	511
Other real estate	1,610	963	648
ATM expense	2,409	2,367	2,033
Trust expense	323	332	314
Other	1,890	1,876	1,813
Totals	$ 9,649	$ 8,793	$ 7,745