Goodwill and Other Intangible Assets - Components of Intangible Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	$ 34,767	$ 37,193
Accumulated amortization	24,483	25,203
Net carrying amount	10,284	11,990
Covenants Not To Compete [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	0	710
Accumulated amortization	0	710
Net carrying amount	0	0
Core Deposits [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	6,788	6,788
Accumulated amortization	4,026	3,143
Net carrying amount	2,762	3,645
Customer Related Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	8,819	12,381
Accumulated amortization	7,923	10,804
Net carrying amount	896	1,577
Servicing Rights [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	19,160	17,314
Accumulated amortization	12,534	10,546
Net carrying amount	$ 6,626	$ 6,768