Revenue from Contracts with Customers - Schedule of Revenue from Contracts (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Disaggregation of Revenue [Line Items]
Total net interest income	$ 23,250	$ 23,199	$ 46,688	$ 45,667
Noninterest income:
Service charges on deposit accounts	2,282	2,064	4,491	4,131
Lockbox fees	992	621	2,081	1,412
Net gains on sales of securities	7		7	197
Gains on sales of mortgage loans	139		154
Other income	1,577	1,037	2,691	2,175
Total noninterest income	4,997	3,722	9,424	7,915
ASU 2014-09 [Member]
Disaggregation of Revenue [Line Items]
Total net interest income	23,250	23,199	46,688	45,667
Noninterest income:
Service charges on deposit accounts	2,282	2,064	4,491	4,131
Lockbox fees	992	621	2,081	1,412
Net gains on sales of securities	7		7	197
Gains on sales of mortgage loans	139		154
Other income	1,577	1,037	2,691	2,175
Total noninterest income	4,997	3,722	9,424	7,915
Total revenues	28,247	26,921	56,112	53,582
ASU 2014-09 [Member] | Revenue Guidance Contracts in Scope of Topic 606 [Member]
Noninterest income:
Service charges on deposit accounts	2,282	2,064	4,491	4,131
Lockbox fees	992	621	2,081	1,412
Other income	810	745	1,610	1,464
Total noninterest income	4,084	3,430	8,182	7,007
Total revenues	$ 4,084	$ 3,430	$ 8,182	$ 7,007