Revenue Recognition - Summary of Noninterest Income Segregated By Revenue Streams (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Noninterest income
Service charges	$ 1,134	$ 1,045
ATM/Interchange fees	554	510
Wealth management fees	852	707
Tax refund processing fees	2,200	2,200
Other	361	275
Total Noninterest Income	5,616	5,138
Noninterest Income (in-scope of Topic 606) [Member]
Noninterest income
Service charges	1,134	1,045
ATM/Interchange fees	554	510
Wealth management fees	852	707
Tax refund processing fees	2,200	2,200
Other	220	194
Total Noninterest Income	4,960	4,656
Noninterest Income (out-of-scope of Topic 606) [Member]
Noninterest income
Total Noninterest Income	$ 656	$ 482