SEGMENT AND GEOGRAPHIC INFORMATION (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Segment Reporting Information
Net sales	$ 333,046	$ 266,754
Operating income/(loss)	33,791	13,821
Total assets	1,281,679		$ 1,272,307
Corporate And Eliminations
Segment Reporting Information
Net sales	(17,100)	(13,000)
Operating income/(loss)	(14,400)	(14,900)
Total assets	108,900		108,500
Water Systems | Operating Segments
Segment Reporting Information
Net sales	197,600	164,100
Operating income/(loss)	31,300	18,800
Total assets	634,700		645,900
Water Systems | United States & Canada
Segment Reporting Information
Net sales	84,200	70,900
Water Systems | United States & Canada | Intersegment Sales
Segment Reporting Information
Net sales	17,100	13,000
Water Systems | Latin America
Segment Reporting Information
Net sales	31,700	28,200
Water Systems | EMEA
Segment Reporting Information
Net sales	44,400	38,200
Water Systems | Asia Pacific
Segment Reporting Information
Net sales	20,200	13,800
Distribution | Operating Segments
Segment Reporting Information
Net sales	95,700	60,400
Operating income/(loss)	2,000	(2,200)
Total assets	270,900		249,000
Distribution | United States & Canada
Segment Reporting Information
Net sales	95,700	60,400
Distribution | United States & Canada | Intersegment Sales
Segment Reporting Information
Net sales	0	0
Fueling Systems | Operating Segments
Segment Reporting Information
Net sales	56,800	55,300
Operating income/(loss)	14,900	12,100
Total assets	267,200		$ 268,900
Fueling Systems | Intersegment Sales
Segment Reporting Information
Net sales	0	0
Fueling Systems | United States & Canada
Segment Reporting Information
Net sales	37,700	37,400
Fueling Systems | All Other
Segment Reporting Information
Net sales	$ 19,100	$ 17,900