Derivatives - Summary Information Regarding Derivatives (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
3rd Party interest rate swaps
Classified in Other Assets:
Notional Amount		$ 85,796
Average Maturity (Years)		9 years
Weighted Average Fixed Rate		3.51%
Fair Value		$ 947
Interest rate		1.95%
Classified in Other Liabilities:
Notional Amount	$ 780,599	$ 473,273
Average Maturity (Years)	9 years 8 months 12 days	9 years 10 months 24 days
Weighted Average Fixed Rate	3.89%	4.32%
Other Liabilities, Fair Value	$ (91,277)	$ (25,905)
Interest rate	1.89%	1.93%
Customer interest rate swaps
Classified in Other Assets:
Notional Amount	$ 780,599	$ 473,273
Average Maturity (Years)	9 years 8 months 12 days	9 years 10 months 24 days
Weighted Average Fixed Rate	3.89%	4.32%
Fair Value	$ 91,277	$ 25,905
Interest rate	1.89%	1.93%
Classified in Other Liabilities:
Notional Amount		$ 85,796
Average Maturity (Years)		9 years
Weighted Average Fixed Rate		3.51%
Other Liabilities, Fair Value		$ (947)
Interest rate		1.95%
Interest Rate Swaps
Classified in Other Assets:
Notional Amount		$ 30,000
Average Maturity (Years)		1 year 6 months
Weighted Average Fixed Rate		1.10%
Fair Value		$ 271
Classified in Other Liabilities:
Notional Amount	$ 30,000
Average Maturity (Years)	1 year 3 months 18 days
Weighted Average Fixed Rate	1.10%
Other Liabilities, Fair Value	$ (207)