Loans and Allowance for Loan Losses - Summary of Nonperforming and Restructured Assets (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Summary Of Nonperforming And Restructured Assets [Abstract]
Past due 90 days or more and still accruing	$ 2,663	$ 1,916
Nonaccrual	17,998	22,603
Restructured	16,486	13,188
Total nonperforming and restructured loans	37,147	37,707
Other real estate owned and repossessed assets	7,004	6,873
Total nonperforming and restructured assets	$ 44,151	$ 44,580