Stock-Based Compensation - Restricted Stock Plan and Performance Shares (Details) - USD ($) $ / shares in Units, $ in Thousands | 3 Months Ended |
Dec. 31, 2021 | Dec. 31, 2020 |
Restricted Stock [Member] | 2009 Restricted Stock Plan | | |
Restricted stock plan activity, number of shares | | |
Unvested and deferred at beginning of the period (in shares) | 142,269 | |
Granted (in shares) | 31,704 | |
Vested and deferred (in shares) | (38,487) | |
Unvested and deferred at end of the period (in shares) | 135,486 | |
Expected to vest (in shares) | 135,486 | |
Restricted stock plan activity, Weighted Average Fair Value at Grant Date | | |
Unvested and deferred at beginning of the period (in dollars per share) | $ 26.78 | |
Granted (in dollars per share) | 44.07 | |
Vested and deferred (in dollars per share) | 30.43 | |
Unvested and deferred at end of the period (in dollars per share) | 29.78 | |
Expected to vest (in dollars per share) | $ 29.78 | |
Deferred Restricted Stock plan activity, number of shares | | |
Vested (in shares) | 38,487 | |
Deferred Restricted Stock plan activity, Weighted Average Fair Value at Grant Date | | |
Vested and deferred (in dollars per share) | $ 30.43 | |
Restricted stock plan activity, other disclosures | | |
Compensation expense | $ 392 | $ 495 |
Remaining unrecognized compensation expense | $ 2,489 | |
Weighted average period for recognition | 1 year 3 months 25 days | |
Restricted Stock [Member] | 2009 Restricted Stock Plan | Employee | | |
Restricted stock plan activity, other disclosures | | |
Repurchase of stock from employees (in shares) | 11,214 | |
Average purchase price (in dollars per share) | $ 43.70 | |
Deferred Restricted Stock | 2016 Restricted Stock Plan | | |
Restricted stock plan activity, number of shares | | |
Vested and deferred (in shares) | (28,833) | |
Restricted stock plan activity, Weighted Average Fair Value at Grant Date | | |
Vested and deferred (in dollars per share) | $ 30.07 | |
Deferred Restricted Stock plan activity, number of shares | | |
Outstanding at beginning of period (in shares) | 7,398 | |
Granted (in shares) | 3,801 | |
Vested and deferred (in shares) | (7,398) | |
Outstanding at end of period (in shares) | 3,801 | |
Vested (in shares) | 28,833 | |
Deferred Restricted Stock plan activity, Weighted Average Fair Value at Grant Date | | |
Outstanding at beginning of period (in dollars per share) | $ 22.64 | |
Granted (in dollars per share) | 44.07 | |
Vested and deferred (in dollars per share) | 22.64 | |
Outstanding at end of period (in dollars per share) | 44.07 | |
Vested and deferred (in dollars per share) | $ 30.07 | |
Restricted stock plan activity, other disclosures | | |
Compensation expense | $ 42 | 63 |
Remaining unrecognized compensation expense | $ 154 | |
Weighted average period for recognition | 11 months 1 day | |
Performance Shares | | |
Restricted stock plan activity, number of shares | | |
Vested and deferred (in shares) | (24,282) | |
Deferred Restricted Stock plan activity, number of shares | | |
Vested (in shares) | 24,282 | |
Performance Shares | Certain Employees | | |
Stock-Based Compensation | | |
Remaining unrecognized compensation expense | $ 2,234 | |
Restricted stock plan activity, number of shares | | |
Unvested and deferred at beginning of the period (in shares) | 87,193 | |
Granted (in shares) | 21,520 | |
Vested and deferred (in shares) | (24,282) | |
Unvested and deferred at end of the period (in shares) | 84,431 | |
Restricted stock plan activity, Weighted Average Fair Value at Grant Date | | |
Unvested and deferred at beginning of the period (in dollars per share) | $ 37.24 | |
Granted (in dollars per share) | 61.04 | |
Vested and deferred (in dollars per share) | 44.93 | |
Unvested and deferred at end of the period (in dollars per share) | $ 41.09 | |
Deferred Restricted Stock plan activity, number of shares | | |
Vested (in shares) | 24,282 | |
Deferred Restricted Stock plan activity, Weighted Average Fair Value at Grant Date | | |
Vested and deferred (in dollars per share) | $ 44.93 | |
Restricted stock plan activity, other disclosures | | |
Stock issued to certain employees | 20,911 | |
Compensation expense | $ 229 | $ 222 |
Weighted average period for recognition | 1 year 9 months 25 days | |