v3.25.4
Income Taxes - Additional Information (Detail)
 12 Months Ended
Dec. 31, 2024
USD ($)
Entity
Dec. 31, 2023
USD ($)
Dec. 31, 2022
USD ($)
Dec. 31, 2021
USD ($)
Dec. 31, 2020
USD ($)
Dec. 31, 2019
USD ($)
Dec. 31, 2011
USD ($)
Dec. 31, 2009
USD ($)
Dec. 31, 2008
Apr. 27, 2018
USD ($)
Income Tax Contingency [Line Items]                    
Enacted tax rate 25.00% 25.00% 25.00% 25.00% 25.00% 25.00%        
Dividend withholding tax rate                 10.00%  
Deferred tax liability on withholding tax on undistributed profits of PRC subsidiaries $ 0 $ 0 $ 0 $ 0 $ 0 $ 0        
Provision for uncertain tax positions 0                  
Interest and penalties related to uncertain tax positions 0 0 0 0 0 0        
Material unrecognized tax benefit 0 0 0 0 0 0        
Net operating losses carryforward indefinitely 3,300,000 3,300,000 3,300,000 3,300,000 3,300,000          
Income tax expense 15,044,000 473,000 2,525,000 14,315,000 6,579,000 $ (2,040,000)        
December 31, 2021                    
Income Tax Contingency [Line Items]                    
Net operating losses carryforward, subjected to expiration         3,200,000          
December 31, 2022                    
Income Tax Contingency [Line Items]                    
Net operating losses carryforward, subjected to expiration       9,600,000 9,300,000          
December 31, 2023                    
Income Tax Contingency [Line Items]                    
Net operating losses carryforward, subjected to expiration     10,200,000 10,800,000 10,500,000          
December 31, 2024                    
Income Tax Contingency [Line Items]                    
Net operating losses carryforward, subjected to expiration   9,600,000 11,700,000 12,300,000 12,800,000          
December 31, 2025                    
Income Tax Contingency [Line Items]                    
Net operating losses carryforward, subjected to expiration 14,700,000 15,000,000 15,800,000 16,700,000 $ 17,200,000          
December 31, 2026                    
Income Tax Contingency [Line Items]                    
Net operating losses carryforward, subjected to expiration 14,100,000 14,400,000 15,100,000 $ 16,100,000            
December 31, 2027                    
Income Tax Contingency [Line Items]                    
Net operating losses carryforward, subjected to expiration 2,900,000 3,000,000 $ 3,100,000              
December 31, 2028                    
Income Tax Contingency [Line Items]                    
Net operating losses carryforward, subjected to expiration 3,700,000 $ 3,700,000                
December 31, 2029                    
Income Tax Contingency [Line Items]                    
Net operating losses carryforward, subjected to expiration 6,600,000                  
Nam Tai Trading Company Limited                    
Income Tax Contingency [Line Items]                    
Total tax claims plus interest 6,600,000                  
Nam Tai Telecom (Hong Kong) Company Limited | Taxable year 2002/2003                    
Income Tax Contingency [Line Items]                    
Total tax claims plus interest             $ 400,000 $ 400,000    
Nam Tai Group Management Limited ("NTGM")                    
Income Tax Contingency [Line Items]                    
Total tax claims plus interest 1,100,000                  
Nam Tai Group Management Limited ("NTGM") | Taxable years 1996/1997, 1997/1998 and 1999/2000                    
Income Tax Contingency [Line Items]                    
Additional tax by way of penalty $ 2,300,000                  
Hong Kong                    
Income Tax Contingency [Line Items]                    
Enacted tax rate 16.50% 16.50% 16.50% 16.50% 16.50% 16.50%        
Number of entities | Entity 3                  
Hong Kong | Nam Tai Group Management Limited ("NTGM") | Taxable years 2001/2002                    
Income Tax Contingency [Line Items]                    
Income tax assessment                   $ 3,000,000
Internal Revenue Service (IRS)                    
Income Tax Contingency [Line Items]                    
Income tax expense $ 0 $ 0 $ 0 $ 0 $ 0 $ 0