Capital Assets (Intangible Assets) (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Mar. 31, 2018	Sep. 30, 2017
Finite-Lived Intangible Assets [Line Items]
Total intangible assets	$ 299,362	$ 296,643
Accumulated Amortization	(48,892)	(41,564)
Intangible assets, net	$ 250,470	$ 255,079
Weighted Average Useful Life (in Years)	14 years 10 months 20 days	15 years
Software development costs
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 27,999	$ 26,083
Accumulated Amortization	(15,859)	(15,830)
Net Carrying Value	$ 12,140	$ 10,253
Weighted Average Useful Life (in Years)	5 years 10 months 20 days	5 years 11 months
Technology and patents
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 47,218	$ 46,731
Accumulated Amortization	(11,212)	(9,399)
Net Carrying Value	$ 36,006	$ 37,332
Weighted Average Useful Life (in Years)	14 years 10 months 24 days	14 years 10 months 24 days
Trademarks and trade names
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 7,208	$ 6,936
Accumulated Amortization	(2,852)	(2,484)
Net Carrying Value	$ 4,356	$ 4,452
Weighted Average Useful Life (in Years)	25 years 7 months 25 days	25 years 7 months
Customer lists
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 157,000	$ 157,016
Accumulated Amortization	(18,342)	(13,359)
Net Carrying Value	$ 138,658	$ 143,657
Weighted Average Useful Life (in Years)	15 years 9 months 18 days	15 years 9 months 18 days
Land-use rights
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 2,437	$ 2,377
Accumulated Amortization	(627)	(492)
Net Carrying Value	$ 1,810	$ 1,885
Weighted Average Useful Life (in Years)	26 years 10 months 15 days	26 years 4 months 15 days
Trade names
Finite-Lived Intangible Assets [Line Items]
Indefinite-lived intangible assets	$ 57,500	$ 57,500