| Computation of Basic and Diluted Net Earnings Per Share | The following table presents the computation of basic and diluted net earnings per share (in $000's):   
       
        |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  
        |   |   | Three Months Ended March 31, |   |   | For the Six Months Ended March 31, |   |  
        |   |   | 2022 |   |   | 2021 |   |   | 2022 |   |   | 2021 |   |  
        | Basic |   |   |   |   |   |   |   |   |   |   |   |   |  
        | Net income |   | $ | 15,358 |   |   | $ | 8,734 |   |   | $ | 21,904 |   |   | $ | 14,147 |   |  
        | Less: preferred stock dividends |   |   | — |   |   |   | — |   |   |   | — |   |   |   | — |   |  
        | Net income applicable to common stock |   | $ | 15,358 |   |   | $ | 8,734 |   |   | $ | 21,904 |   |   | $ | 14,147 |   |  
        |    |   |   |   |   |   |   |   |   |   |   |   |   |  
        | Weighted average common shares outstanding |   |   | 3,134,540 |   |   |   | 1,555,175 |   |   |   | 3,148,059 |   |   |   | 1,534,287 |   |  
        | Basic earnings per share |   | $ | 4.90 |   |   | $ | 5.62 |   |   | $ | 6.96 |   |   | $ | 9.22 |   |  
        |    |   |   |   |   |   |   |   |   |   |   |   |   |  
        | Diluted |   |   |   |   |   |   |   |   |   |   |   |   |  
        | Net income applicable to common stock |   | $ | 15,358 |   |   | $ | 8,734 |   |   | $ | 21,904 |   |   | $ | 14,147 |   |  
        | Add: preferred stock dividends |   |   | — |   |   |   | — |   |   |   | — |   |   |   | — |   |  
        | Net income applicable for diluted earnings per share |   | $ | 15,358 |   |   | $ | 8,734 |   |   | $ | 21,904 |   |   | $ | 14,147 |   |  
        |    |   |   |   |   |   |   |   |   |   |   |   |   |  
        | Weighted average common shares outstanding |   |   | 3,134,540 |   |   |   | 1,555,175 |   |   |   | 3,148,059 |   |   |   | 1,534,287 |   |  
        | Add: Options |   |   | 38,102 |   |   |   | 87,168 |   |   |   | 38,825 |   |   |   | 87,168 |   |  
        | Add: Series B Preferred Stock |   |   | — |   |   |   | 1,593,950 |   |   |   | — |   |   |   | 1,593,950 |   |  
        | Add: Series E Preferred Stock |   |   | 239 |   |   |   | 47,840 |   |   |   | 239 |   |   |   | 47,840 |   |  
        | Assumed weighted average common shares outstanding |   |   | 3,172,881 |   |   |   | 3,284,133 |   |   |   | 3,187,124 |   |   |   | 3,263,245 |   |  
        | Diluted earnings per share |   | $ | 4.84 |   |   | $ | 2.66 |   |   | $ | 6.87 |   |   | $ | 4.34 |   |  |