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Federal, State and Local Taxes - Reconciliation of Statutory Federal Income Tax Expense (Benefit) Reported in Net Income to Combined Actual Income Tax Expense (Benefit) (Parenthetical) (Detail)
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Income Tax Disclosure [Abstract]      
Statutory federal income tax rate 21.00% 21.00% 21.00%