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Summary of Significant Accounting Policies (Details) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Sep. 30, 2019 | Sep. 30, 2018 | Sep. 30, 2017
Accounting Policies [Abstract] |  |  |
Deferred financing cost amortization | $ 318 | $ 288 | $ 294
Debt Issuance Costs, Noncurrent, Net | 782 | 912 |
Accounts Receivable, Allowance for Credit Loss | (1,184) | (868) | $ (650)
Deferred tax assets | $ 40,874 | $ 46,580 |
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent | 21.00% | 24.53% | 35.00%
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount |  | $ 31,333 |
Loss Contingency, Undiscounted Amount of Insurance-related Assessment Liability | $ 4,975 | $ 5,286 |
Accrual for Loss Contingencies, Undiscounted, First Year | 1,422 |  |
Accrual for Loss Contingencies, Undiscounted, Second Year | 1,065 |  |
Accrual for Loss Contingencies, Undiscounted, Third Year | 727 |  |
Accrual for Loss Contingencies, Undiscounted, Fourth Year | 504 |  |
Accrual for Loss Contingencies, Undiscounted, Fifth Year | 290 |  |
Accrual for Insurance Loss Contingencies, Undiscounted, after Fifth Year | $ 967 |  |
Loss Contingency Accrual, Insurance-related Assessment, Discount Rate | 1.60% | 2.90% |
Accrued Insurance, Current | $ 6,683 | $ 6,202 |
Letters of Credit Outstanding, Amount | $ 6,468 |  |
Noncontrolling Interest, Ownership Percentage by Parent | 80.00% |  |
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners | 20.00% |  |
Redeemable Noncontrolling Interest, Equity, Redemption Value | $ 3,294 |  |
Noncontrolling Interest, Change in Redemption Value |  | $ 44 | $ (44)
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification | $ 35,000 |  |

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