Goodwill and Other Intangible Assets (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Finite-Lived Intangible Assets [Line Items]
Amortization expense related to intangible assets	$ 16,338	$ 11,630	$ 8,850
Estimated intangible asset amortization for 2021	$ 20,000
Customer Relationships [Member] | Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Expected remaining useful life	20 years
Customer Relationships [Member] | Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Expected remaining useful life	15 years
Patents [Member]
Finite-Lived Intangible Assets [Line Items]
Expected remaining useful life	17 years
Capitalized Software [Member] | Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Expected remaining useful life	7 years
Capitalized Software [Member] | Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Expected remaining useful life	3 years