Earnings per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Numerator:
Numerator for basic and diluted earnings per common share—Net income attributable to Evoqua Water Technologies Corp.	$ 17,563	$ 13,155	$ 30,880	$ 24,624
Denominator:
Denominator for basic net income per common share—weighted average shares	121,338	119,015	120,970	119,015
Effect of dilutive securities:
Share‑based compensation	3,512	3,245	3,927	3,312
Denominator for diluted net income per common share—adjusted weighted average shares	124,850	122,260	124,897	122,327
Basic income per common share	$ 0.14	$ 0.11	$ 0.26	$ 0.21
Diluted income per common share	$ 0.14	$ 0.11	$ 0.25	$ 0.20