v3.26.3
Significant Accounting Policies - Additional Information (Detail)
 3 Months Ended 9 Months Ended
Jan. 04, 2023
Sep. 30, 2026
USD ($)
$ / shares
shares
Sep. 30, 2025
USD ($)
shares
Sep. 30, 2026
USD ($)
Segment
$ / shares
shares
Sep. 30, 2025
USD ($)
shares
Dec. 31, 2025
USD ($)
$ / shares
Significant Accountings Policies [Line Items]            
Bank partner deposits   $ 20,793,000   $ 20,793,000   $ 3,618,000
Loan origination costs   1,100,000 $ 1,700,000 4,600,000 $ 4,200,000  
Revenues   197,704,000 150,725,000 526,911,000 390,461,000  
Valuation allowance     27,400,000      
Unrecognized tax benefits, income tax penalties and interest accrued   3,900,000   3,900,000   3,300,000
FDIC insured amount   270,800,000   $ 270,800,000   $ 81,400,000
Installment fee       3.00%    
Allowance for credit losses average term       12 days    
Capitalized costs for internally developed software   2,100,000 1,700,000 $ 6,100,000 4,800,000  
Advertising costs   25,100,000 16,400,000 55,600,000 40,100,000  
Activation costs   $ 2,900,000 $ 2,500,000 $ 6,900,000 $ 6,200,000  
Accounts receivable, noncurrent, threshold period past due, writeoff   120 days   120 days    
Accounts receivable, noncurrent, threshold period past due   13 days   13 days    
Threshold for purchase of receivables remains outstanding after origination minimum period       60 days    
Threshold for purchase of receivables   60 days   60 days    
Computation of diluted net income excluded | shares   1,216,176 770,488 1,246,452 831,807  
Reverse stock split, conversion ratio 0.03125          
Dilutive warrants | shares     0   0  
Number of reportable segments | Segment       1    
Number of operating segments | Segment       1    
Segment Reporting, CODM, Individual Title and Position or Group Name [Extensible Enumeration]       Chief Executive Officer [Member], srt:ChiefFinancialOfficerMember    
Conversion price | $ / shares   $ 279.13   $ 279.13    
Incremental shares to settle the conversion premium on 2031 Notes | shares   177,096        
Incremental shares included to determined the year-to-date weighted average | shares       59,032    
After The Completion Of A Business Combination Or Earlier Upon Redemption Or Liquidation [Member]            
Significant Accountings Policies [Line Items]            
Exercise price of warrants | $ / shares   $ 11.5   $ 11.5    
After The Completion Of A Business Combination Or Earlier Upon Redemption Or Liquidation [Member] | Warrants [Member]            
Significant Accountings Policies [Line Items]            
Exercise price of warrants | $ / shares   $ 368   $ 368    
Accounting Standards Update 2024-04 [Member]            
Significant Accountings Policies [Line Items]            
Change in Accounting Principle, Accounting Standards Update, Adopted [true false]   true   true    
Change in Accounting Principle, Accounting Standards Update, Adoption Date   Jan. 01, 2026   Jan. 01, 2026    
Change in Accounting Principle, Accounting Standards Update, Immaterial Effect [true false]   true   true    
Accounting Standards Update 2025-05 [Member]            
Significant Accountings Policies [Line Items]            
Change in Accounting Principle, Accounting Standards Update, Adopted [true false]   true   true    
Change in Accounting Principle, Accounting Standards Update, Adoption Date   Jan. 01, 2026   Jan. 01, 2026    
Change in Accounting Principle, Accounting Standards Update, Immaterial Effect [true false]   true   true    
Minimum [Member]            
Significant Accountings Policies [Line Items]            
Property, plant and equipment, useful life   3 years   3 years    
Minimum [Member] | Performance-Based Restricted Stock Units [Member]            
Significant Accountings Policies [Line Items]            
Non-option equity units percentage of target shares granted       0.00%    
Maximum [Member]            
Significant Accountings Policies [Line Items]            
Property, plant and equipment, useful life   7 years   7 years    
Maximum [Member] | Performance-Based Restricted Stock Units [Member]            
Significant Accountings Policies [Line Items]            
Non-option equity units percentage of target shares granted       200.00%    
Class A common stock [Member]            
Significant Accountings Policies [Line Items]            
Common Stock, Par Value | $ / shares   $ 0.0001   $ 0.0001   $ 0.0001
Average market price | $ / shares   370.78        
Class V common stock [Member]            
Significant Accountings Policies [Line Items]            
Common Stock, Par Value | $ / shares   $ 0.0001   $ 0.0001   $ 0.0001
Earnout Shares [Member]            
Significant Accountings Policies [Line Items]            
Computation of diluted net income excluded | shares     49,563   49,563  
Members' Usage of Out-of-Network [Member]            
Significant Accountings Policies [Line Items]            
ATM-related fees   $ 600,000 $ 700,000 $ 1,900,000 $ 2,300,000  
Transaction based revenue, net [Member]            
Significant Accountings Policies [Line Items]            
Revenues   11,355,000 11,496,000 32,928,000 31,788,000  
ATM-related fees   500,000 600,000 1,700,000 1,800,000  
Tips [Member]            
Significant Accountings Policies [Line Items]            
Revenues   $ 0 $ 0 $ 0 $ 7,496,000  
Internally Developed Software [Member]            
Significant Accountings Policies [Line Items]            
Finite-lived intangible asset, useful life   3 years   3 years