Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Statement of Comprehensive Income [Abstract]
Net (loss) income	$ (8,471)	$ 7,884	$ 6,410
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Foreign currency translation adjustments	1,507	(3,473)	148
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, after Tax	74	(21)	(19)
Change in pension liability, net of tax expense of $26, $232 and $0, respectively	(5,568)	466	4,553
Total other comprehensive (loss) income	(3,987)	(3,028)	4,682
Less: Comprehensive income attributable to non‑controlling interest	(1,052)	(1,749)	(4,247)
Comprehensive (loss) income attributable to Evoqua Water Technologies Corp.	$ (13,510)	$ 3,107	$ 6,845