Income Taxes - Components of Income Tax Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Current
Federal	$ 267,550	$ 359,668	$ 408,428
State and local	98,431	132,696	113,706
Total current	365,981	492,364	522,134
Deferred
Federal	(22,894)	40,769	(12,780)
State and local	(8,397)	16,779	28,637
Total deferred	(31,291)	57,548	15,857
Amortization of investments in qualified affordable housing projects	81,679	68,200	52,169
Income taxes	$ 416,369	$ 618,112	$ 590,160