Quarterly report pursuant to Section 13 or 15(d)

Income Taxes - Additional Information (Detail)

v3.19.1
Income Taxes - Additional Information (Detail) - USD ($)
3 Months Ended 12 Months Ended
Mar. 31, 2019
Mar. 31, 2018
Dec. 31, 2017
Dec. 31, 2018
Tax Credit Carryforward [Line Items]        
Unrecognized tax benefits $ 0 $ 0    
Interest or penalties related to uncertain tax positions 0 0    
Prepaid taxes 100,000     $ 100,000
Deferred tax assets 2,400,000     2,100,000
Deferred tax liability $ 1,700,000     $ 1,600,000
Corporate income tax rate 21.00%   35.00%  
Tax Year 2013 [Member]        
Tax Credit Carryforward [Line Items]        
Tax years open to examination 2015      
Tax Year 2018 [Member]        
Tax Credit Carryforward [Line Items]        
Tax years open to examination 2018      
General and Administrative Expense [Member]        
Tax Credit Carryforward [Line Items]        
Federal and state income tax expense (benefit) $ 400,000 $ 500,000