Income Taxes - Components of Income Tax Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Current
Federal	$ 130,349	$ 378,978	$ 371,249
State and city	21,549	50,790	68,035
Total current	151,898	429,768	439,284
Deferred
Federal	324,317	65,503	106,537
State and city	72,279	27,345	33,248
Total deferred	396,596	92,848	139,785
Amortization of investments in qualified affordable housing projects	46,531	53,383	48,019
Income taxes	$ 595,025	$ 575,999	$ 627,088