Fair Value - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Provision for loan loss expense on impaired loans	$ 44,914	$ 1,053
Repossessed real estate owned valuation write down	95	108
Impairment on bank property held for sale	31	107
Non-PCD Impaired Loans [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Impaired loans with allocated allowance for loan losses	22,169		$ 18,556
Impaired valuation allowance	1,789		$ 1,708
Provision for loan loss expense on impaired loans	911	$ 1,124
PCD Impaired Loans [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Impaired loans with allocated allowance for loan losses	22,776
Impaired valuation allowance	12,316
Provision for loan loss expense on impaired loans	$ 2,870
Minimum [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Capitalization rates to determine fair value of collateral	5.00%
Minimum [Member] | Interest Rate Lock Commitments [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Fair value of servicing rights expected to be recorded upon estimated gain on sale of loan, percentage	(1.45%)		(2.41%)
Fair value of servicing rights expected to be recorded upon estimated cost to originate rate, percentage	0.70%		0.70%
Fair value of servicing rights expected to be recorded upon pull through rate, percentage	47.00%		58.00%
Maximum [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Capitalization rates to determine fair value of collateral	13.00%
Maximum [Member] | Interest Rate Lock Commitments [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Fair value of servicing rights expected to be recorded upon estimated gain on sale of loan, percentage	9.34%		8.21%
Fair value of servicing rights expected to be recorded upon estimated cost to originate rate, percentage	0.89%		0.89%
Fair value of servicing rights expected to be recorded upon pull through rate, percentage	100.00%		100.00%
Weighted Average | Interest Rate Lock Commitments [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Fair value of servicing rights expected to be recorded upon estimated gain on sale of loan, percentage	3.19%		2.54%
Fair value of servicing rights expected to be recorded upon estimated cost to originate rate, percentage	0.82%		0.82%
Fair value of servicing rights expected to be recorded upon pull through rate, percentage	85.19%		89.00%