SEGMENT AND GEOGRAPHIC INFORMATION (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Segment Reporting Information
Net sales	$ 351,190	$ 348,416	$ 926,225	$ 994,471
Operating income/(loss)	48,384	42,719	96,138	98,531
Total assets	1,201,442		1,201,442		$ 1,194,743
Corporate And Eliminations
Segment Reporting Information
Net sales	(18,100)	(16,500)	(49,300)	(42,500)
Operating income/(loss)	(13,500)	(13,200)	(43,400)	(41,700)
Total assets	108,900		108,900		72,400
Water Systems | Operating Segments
Segment Reporting Information
Net sales	202,900	199,800	545,400	593,200
Operating income/(loss)	36,600	28,400	84,100	78,500
Total assets	628,600		628,600		658,300
Water Systems | United States & Canada
Segment Reporting Information
Net sales	93,400	94,900	245,100	284,800
Water Systems | United States & Canada | Intersegment Sales
Segment Reporting Information
Net sales	18,100	16,500	49,300	42,500
Water Systems | Latin America
Segment Reporting Information
Net sales	30,100	30,600	82,500	90,500
Water Systems | EMEA
Segment Reporting Information
Net sales	41,800	40,800	115,500	117,500
Water Systems | Asia Pacific
Segment Reporting Information
Net sales	19,500	17,000	53,000	57,900
Distribution | Operating Segments
Segment Reporting Information
Net sales	98,000	87,000	250,500	227,400
Operating income/(loss)	6,400	5,900	10,900	6,100
Total assets	195,800		195,800		180,200
Distribution | United States & Canada
Segment Reporting Information
Net sales	98,000	87,000	250,500	227,400
Distribution | United States & Canada | Intersegment Sales
Segment Reporting Information
Net sales	0	0	0	0
Fueling Systems | Operating Segments
Segment Reporting Information
Net sales	68,400	78,100	179,600	216,400
Operating income/(loss)	18,900	21,600	44,500	55,600
Total assets	268,100		268,100		$ 283,800
Fueling Systems | Intersegment Sales
Segment Reporting Information
Net sales	0	0	0	0
Fueling Systems | United States & Canada
Segment Reporting Information
Net sales	46,400	48,300	119,000	129,300
Fueling Systems | All Other
Segment Reporting Information
Net sales	$ 22,000	$ 29,800	$ 60,600	$ 87,100