Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Deferred tax assets:
Allowance for loan losses	$ 12,788	$ 11,207	$ 10,389
Compensation and benefits	7,144	5,851	2,536
Security gains	3,031	3,707	821
Purchase accounting adjustments			1,565
Non-accrual interest income	1,297	1,388	1,389
Tax credit carryforwards	149		5,204
Net operating loss carryforwards	6,923	4,854	6,062
Fair value adjustments on securities available-for-sale		6,345	3,962
Lease accrual	13,787
Other	2,314	2,125	1,118
Gross deferred tax assets	47,433	35,477	33,046
Deferred tax liabilities:
Depreciation and amortization	(4,014)	(1,020)	(1,883)
Accretion on securities	(339)	(461)	(266)
Deferred fees and costs	(2,388)	(1,641)	(2,989)
Purchase accounting adjustments	(2,787)	(1,003)
Fair value adjustments on securities available-for-sale	(5,749)
Partnership adjustments	(521)	(680)	(674)
Lease - right of use assets	(13,064)
Other	(40)	(367)	(120)
Gross deferred tax liabilities	(28,902)	(5,172)	(5,932)
Net deferred tax assets	$ 18,531	$ 30,305	$ 27,114