Supporting Financial Information - Accounts Payable, Accrued Expense and Other Current Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Sep. 30, 2018
Business Acquisition [Line Items]
Accounts payable	$ 9,290	$ 3,393
Accrued benefits	2,173	2,060
Accrued bonus and incentive compensation	1,577	2,191
Accrued workers compensation insurance	3,836	2,642
Other accrued expenses	2,217	664
Accounts payable, accrued expenses, and other current liabilities	19,093	$ 10,950
SSS acquisition
Business Acquisition [Line Items]
Accounts payable, accrued expenses, and other current liabilities	$ 4,900