v3.26.3
Business, Basis of Presentation and Summary of Significant Accounting Policies - Narrative (Details)
3 Months Ended 9 Months Ended
Oct. 21, 2026
USD ($)
$ / shares
Sep. 17, 2026
USD ($)
Sep. 30, 2026
USD ($)
$ / shares
shares
Jun. 30, 2026
$ / shares
shares
Mar. 31, 2026
$ / shares
shares
Sep. 30, 2025
$ / shares
shares
Jun. 30, 2025
$ / shares
shares
Mar. 31, 2025
$ / shares
shares
Sep. 30, 2026
USD ($)
segment
shares
Sep. 30, 2025
USD ($)
shares
Oct. 20, 2026
USD ($)
Jan. 31, 2026
USD ($)
Class of Stock [Line Items]                        
Repurchase of common stock - Class A                 $ 37,077,000 $ 20,000,000    
Treasury stock (in shares) | shares     0     0     0 0    
Impairment of equity investment     $ 0           $ 1,800,000      
Equity method investments, fintech     $ 0           $ 0      
Dividends declared (in dollars per share) | $ / shares     $ 0.09 $ 0.09 $ 0.09 $ 0.09 $ 0.09 $ 0.09        
Number of operating segments | segment                 1      
Initial ACL on acquired PSLs     $ 2,481,000           $ 4,841,000      
Common Stock                        
Class of Stock [Line Items]                        
Repurchase of common stock (in shares) | shares     70,592 690,000 859,493 487,657 275,666 215,427        
Subsequent Event                        
Class of Stock [Line Items]                        
Dividends declared (in dollars per share) | $ / shares $ 0.09                      
Class A Common Stock | Common Stock                        
Class of Stock [Line Items]                        
Repurchase of common stock (in shares) | shares                 1,620,085 978,750    
Repurchase of common stock - Class A                 $ 37,100,000 $ 20,000,000.0    
Class A Common Stock | Stock Repurchase Program                        
Class of Stock [Line Items]                        
Stock repurchase program, authorized amount                       $ 40,000,000
Class A Common Stock | Stock Repurchase Program | Subsequent Event                        
Class of Stock [Line Items]                        
Share repurchase program, remaining authorized amount                     $ 3,000,000  
Class A Common Stock | Stock Repurchase Program | Subsequent Event | Minimum                        
Class of Stock [Line Items]                        
Stock repurchase program, authorized amount $ 40,000,000                      
Class A Common Stock | Stock Repurchase Program | Subsequent Event | Maximum                        
Class of Stock [Line Items]                        
Stock repurchase program, authorized amount $ 50,000,000                      
Seven Percent Senior Notes due 2031 | Senior notes                        
Class of Stock [Line Items]                        
Face amount   $ 50,000,000.0                    
Interest rate, stated percentage   7.00%                    
Debt issuance costs   $ 1,600,000                    
Proceeds from issuance of debt   $ 48,400,000                    
Debt issuance costs, amortization period   5 years                    
Amerant Bank, N.A                        
Class of Stock [Line Items]                        
Ownership percentage of subsidiary     100.00%           100.00%