The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

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Supporting Financial Information - Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Sep. 30, 2018
Finite-Lived Intangible Assets [Line Items]
Intangible assets, gross	$ 46,924		$ 46,924		$ 17,623
Total accumulated amortization	(5,768)		(5,768)		(4,258)
Intangible assets, net	41,156		$ 41,156		13,365
Estimated useful live of intangible assets			10 years
Amortization expense of intangible assets	600	$ 400	$ 1,500	$ 1,300
SSS
Finite-Lived Intangible Assets [Line Items]
Amortization expense of intangible assets	200
Customer contracts and related customer relationships
Finite-Lived Intangible Assets [Line Items]
Intangible assets, gross	16,626		16,626		16,626
Total accumulated amortization	(5,266)		(5,266)		(4,018)
Covenants not to compete
Finite-Lived Intangible Assets [Line Items]
Intangible assets, gross	480		480		480
Total accumulated amortization	(152)		(152)		(116)
Trade name
Finite-Lived Intangible Assets [Line Items]
Intangible assets, gross	517		517		517
Total accumulated amortization	(164)		(164)		(124)
Other Intangibles \| SSS
Finite-Lived Intangible Assets [Line Items]
Intangible assets, gross	29,301		29,301		0
Total accumulated amortization	$ (186)		$ (186)		$ 0