Premises and Equipment, Net and Other Assets - Summary of Premises and Equipment by Classification (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Property Plant And Equipment [Line Items]
Accumulated depreciation	$ (133,672)	$ (134,022)
Premises and equipment, net	269,047	261,677
Land [Member]
Property Plant And Equipment [Line Items]
Premises and Equipment, gross	44,588	45,792
Buildings [Member]
Property Plant And Equipment [Line Items]
Premises and Equipment, gross	$ 256,738	201,606
Buildings [Member] | Minimum [Member]
Property Plant And Equipment [Line Items]
Estimated Useful Lives	10 years
Buildings [Member] | Maximum [Member]
Property Plant And Equipment [Line Items]
Estimated Useful Lives	40 years
Furniture Fixtures and Equipment [Member]
Property Plant And Equipment [Line Items]
Premises and Equipment, gross	$ 89,058	87,001
Furniture Fixtures and Equipment [Member] | Minimum [Member]
Property Plant And Equipment [Line Items]
Estimated Useful Lives	3 years
Furniture Fixtures and Equipment [Member] | Maximum [Member]
Property Plant And Equipment [Line Items]
Estimated Useful Lives	15 years
Construction in Progress [Member]
Property Plant And Equipment [Line Items]
Premises and Equipment, gross	$ 12,335	$ 61,300