Income Taxes (Income Tax Computed by Applying U.S. Federal Statutory Income Tax Rate) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Income tax expense computed at the statutory rate	$ 149,598	$ 140,454	$ 102,803
Effect of tax-exempt interest	(43,114)	(50,602)	(50,740)
Tax benefit on dividends paid in our 401k plan	(2,135)	(1,854)	(1,764)
Net tax benefit from stock-based compensation	(894)	(4,602)	(7,877)
Non-deductible FDIC premiums	5,263	3,277	2,629
Non-deductible compensation	2,591	2,250	1,773
Non-deductible meals and entertainment	1,692	683	625
Tax basis adjustment of premises and equipment	0	0	(1,026)
Other	1,399	71	36
Income tax expense, as reported	$ 114,400	$ 89,677	$ 46,459