Premises and Equipment - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Property Plant And Equipment Capitalized Interest Costs [Abstract]
Operating lease liabilities	$ 487,555
Period of noncancelable operating lease in years	22 years
Net lease expense		$ 111,000	$ 114,000