Goodwil and Intangible Assets - Other Intangible Assets (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Jun. 30, 2018	Sep. 30, 2017
IntangibleAssets [Line Items]
Gross Carrying Amount	$ 44,522	$ 40,969
Accumulated Amortization	12,786	9,556
Intangible assets, net	31,736	31,413
Trademarks And Trade Names [Member]
IntangibleAssets [Line Items]
Gross Carrying Amount	5,044	4,643
Accumulated Amortization	723	440
Intangible assets, net	$ 4,321	$ 4,203
Trademarks And Trade Names [Member] | Maximum [Member]
IntangibleAssets [Line Items]
Estimated Useful Lives	20 years	20 years
Trademarks And Trade Names [Member] | Minimum [Member]
IntangibleAssets [Line Items]
Estimated Useful Lives	5 years	5 years
Technical Library [Member]
IntangibleAssets [Line Items]
Estimated Useful Lives	20 years	20 years
Gross Carrying Amount	$ 400	$ 400
Accumulated Amortization	96	81
Intangible assets, net	304	319
Customer Relationships [Member]
IntangibleAssets [Line Items]
Gross Carrying Amount	33,469	31,115
Accumulated Amortization	7,027	4,741
Intangible assets, net	$ 26,442	$ 26,374
Customer Relationships [Member] | Maximum [Member]
IntangibleAssets [Line Items]
Estimated Useful Lives	15 years	15 years
Customer Relationships [Member] | Minimum [Member]
IntangibleAssets [Line Items]
Estimated Useful Lives	6 years	6 years
Order Backlog [Member]
IntangibleAssets [Line Items]
Estimated Useful Lives	1 year	1 year
Gross Carrying Amount	$ 3,026	$ 2,412
Accumulated Amortization	2,565	2,130
Intangible assets, net	$ 461	$ 282
Construction Contract Value [Member]
IntangibleAssets [Line Items]
Estimated Useful Lives	1 year	1 year
Gross Carrying Amount	$ 2,583	$ 2,399
Accumulated Amortization	2,375	2,164
Intangible assets, net	$ 208	$ 235