SEGMENT AND GEOGRAPHIC INFORMATION (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Segment Reporting Information
Net sales	$ 348,416	$ 341,866	$ 994,471	$ 981,466
Operating income/(loss)	42,719	40,137	98,531	103,311
Total assets	1,236,940		1,236,940		$ 1,182,365
Segment Change
Segment Reporting Information
Net sales		1,000		2,800
Operating income/(loss)		0		200
Operating Segments | Water Systems
Segment Reporting Information
Net sales	199,800	199,300	593,200	603,300
Operating income/(loss)	28,400	28,400	78,500	85,700
Total assets	690,200		690,200		679,700
Operating Segments | Distribution
Segment Reporting Information
Net sales	87,000	78,000	227,400	213,700
Operating income/(loss)	5,900	3,100	6,100	6,300
Total assets	199,000		199,000		165,100
Operating Segments | Fueling Systems
Segment Reporting Information
Net sales	78,100	77,800	216,400	209,500
Operating income/(loss)	21,600	20,900	55,600	53,600
Total assets	294,000		294,000		275,700
Intersegment Sales | Distribution
Segment Reporting Information
Net sales	0	0	0	0
Intersegment Sales | Fueling Systems
Segment Reporting Information
Net sales	0	0	0	0
Corporate And Eliminations
Segment Reporting Information
Net sales	(16,500)	(13,200)	(42,500)	(45,000)
Operating income/(loss)	(13,200)	(12,300)	(41,700)	(42,300)
Total assets	53,700		53,700		$ 61,900
United States & Canada | Water Systems
Segment Reporting Information
Net sales	94,900	97,000	284,800	280,000
United States & Canada | Distribution
Segment Reporting Information
Net sales	87,000	78,000	227,400	213,700
United States & Canada | Fueling Systems
Segment Reporting Information
Net sales	48,300	43,700	129,300	113,200
United States & Canada | Intersegment Sales | Water Systems
Segment Reporting Information
Net sales	16,500	13,200	42,500	45,000
Latin America | Water Systems
Segment Reporting Information
Net sales	30,600	31,000	90,500	89,000
EMEA | Water Systems
Segment Reporting Information
Net sales	40,800	40,800	117,500	132,200
EMEA | Segment Change
Segment Reporting Information
Net sales		3,400		10,000
Asia Pacific | Water Systems
Segment Reporting Information
Net sales	17,000	17,300	57,900	57,100
All Other | Fueling Systems
Segment Reporting Information
Net sales	$ 29,800	$ 34,100	$ 87,100	$ 96,300