Revenue (Contract Assets and Liabilities) (Details) - USD ($) $ in Thousands	9 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Sep. 30, 2019	Sep. 30, 2018
Revenue from Contract with Customer [Abstract]
Contract liabilities	$ 30,841	$ 32,312	$ 39,051	$ 17,652
Change in Contract with Customer, Asset [Roll Forward]
beginning of period	73,467	69,147
Cumulative effect of adoption of new accounting standards	0	(6,106)
Recognized in current period	255,623	225,341
Reclassified to accounts receivable	(253,199)	(218,433)
Amounts related to sale of the Memcor product line	2,710	0
Foreign currency	(1,011)	69
end of period	77,590	70,018
Change in Contract with Customer, Liability [Roll Forward]
Cumulative effect of adoption of new accounting standards		1,773
Recognized in current period	241,468	214,444
Amounts in beginning balance reclassified to revenue	(37,508)	(20,127)
Current period amounts reclassified to revenue	(210,985)	(181,266)
Amounts related to sale of the Memcor product line	(700)	0
Foreign currency	$ (485)	$ (164)