Derivative Financial Instruments - Summary of Interest Rate Swaps Designated as Fair Value Hedges (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount	$ 665,500,000	$ 1,482,000,000
Fixed Interest Swap [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount	$ 130,500,000	$ 757,000,000
Weighted average pay rates	1.82%	2.48%
Weighted average receive rates	2.20%	2.70%
Weighted average maturity (in years)	2 years 9 months 18 days	3 years 10 months 24 days
Fair value of swaps	$ 1,555,000	$ 9,683,000