Reconciliation of Statutory Federal Income Tax Expense (Benefit) Reported in Net Income to Combined Actual Income Tax Expense (Benefit) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Reconciliation of Provision of Income Taxes [Line Items]
Statutory federal income tax at 21%, 21% and 35%, respectively	$ 109,894	$ 117,111	$ 233,875
State and local income taxes, net of federal income tax effect	18,346	24,451	29,204
Effect of tax law changes		1,625	(41,943)
Non-deductible FDIC deposit insurance premiums	6,938	8,852
Effect of tax deductibility of ESOP	(3,163)	(3,116)	(5,083)
Non-taxable income and expense of BOLI	(5,981)	(5,957)	(9,529)
Federal tax credits	(750)	(531)	(1,386)
Adjustments relating to prior tax years	373	(7,246)	144
Other, net	2,607	63	(3,268)
Income tax expense reported in net income	$ 128,264	$ 135,252	$ 202,014