Note 12 - Segment Information - Summary of Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Revenue	$ 37,223	$ 50,032
Income (loss) from operations	7,835	12,837
Segment Reporting, Reconciling Item, Corporate Nonsegment [Member]
Revenue	76	74
Income (loss) from operations	(4,877)	(3,135)
Smart Water [Member] | Operating Segments [Member]
Revenue	7,288	4,234
Income (loss) from operations	370	1,095
Energy Solutions [Member] | Operating Segments [Member]
Revenue	24,282	39,911
Income (loss) from operations	13,282	15,068
Intelligent Industrial [Member] | Operating Segments [Member]
Revenue	5,577	5,813
Income (loss) from operations	$ (940)	$ (191)