Revenue (Contract Assets and Liabilities) (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
Revenue from Contract with Customer [Abstract]
Contract liabilities	$ 43,634	$ 31,089	$ 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	84,596	51,567
Reclassified to accounts receivable	87,046	(59,305)
Amounts related to sale of the Memcor product line	2,710	0
Foreign currency	182	345
end of period	73,909	55,648
Change in Contract with Customer, Liability [Roll Forward]
Cumulative effect of adoption of new accounting standards	0	1,773
Recognized in current period	88,616	67,852
Amounts in beginning balance reclassified to revenue	(37,624)	(15,825)
Current period amounts reclassified to revenue	(46,083)	(40,709)
Amounts related to sale of the Memcor product line	(700)	0
Foreign currency	$ 374	$ 346