XML 150 R104.htm IDEA: XBRL DOCUMENT v3.20.4
Income Taxes - Additional Information (Detail) - USD ($)
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2020
Income Taxes [Line Items]        
Federal tax rate   21.00% 34.00%  
Valuation allowance       $ 0
Reduction in sequestration reversal accrual $ 438,000      
Unrecognized tax benefits       0
Accrued interest and penalties related to uncertain tax positions       $ 0