Fair Value - Fair Value Measurement (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assumed Gain/(Loss) From Loan Sale	$ 3,808
Interest Rate Movement Effect	120
Servicing Rights Value	10,726
Security Price Change	(543)
Total Fair Value Measurement Gain/(Loss)	14,111	$ 14,309
Mortgage Banking: | Level 2 | Fair Value, Measurements, Recurring | Rate lock commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Disclosure, Off-balance Sheet Risks, Face Amount, Liability	581,065
Assumed Gain/(Loss) From Loan Sale	1,832
Interest Rate Movement Effect	405
Servicing Rights Value	5,398
Security Price Change	0
Total Fair Value Measurement Gain/(Loss)	7,635
Mortgage Banking: | Level 2 | Fair Value, Measurements, Recurring | Forward sales contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Disclosure, Off-balance Sheet Risks, Face Amount, Liability	986,041
Assumed Gain/(Loss) From Loan Sale	0
Interest Rate Movement Effect	0
Servicing Rights Value	0
Security Price Change	(543)
Total Fair Value Measurement Gain/(Loss)	(543)
Mortgage Banking: | Level 2 | Fair Value, Measurements, Recurring | Mortgages held for sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notional or Principal Amount	485,106	$ 447,444
Assumed Gain/(Loss) From Loan Sale	1,976
Interest Rate Movement Effect	(285)
Servicing Rights Value	5,328
Security Price Change	0
Total Fair Value Measurement Gain/(Loss)	$ 7,019