SEGMENT INFORMATION (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Segment Reporting Information
Net sales	$ 343,970	$ 305,349	$ 639,600	$ 525,601
Operating income/(loss)	40,474	34,271	63,174	52,776
Total assets	1,215,746		1,215,746		$ 1,185,353
Distribution
Segment Reporting Information
Net sales
Fueling Systems
Segment Reporting Information
Net sales
Operating Segments | Water Systems
Segment Reporting Information
Net sales	210,400	198,300	402,200	365,900
Operating income/(loss)	32,300	32,800	57,500	54,200
Total assets	685,600		685,600		695,400
Operating Segments | Distribution
Segment Reporting Information
Net sales	79,500	59,100	135,700	59,100
Operating income/(loss)	4,000	3,700	3,200	3,700
Total assets	185,700		185,700		153,100
Operating Segments | Fueling Systems
Segment Reporting Information
Net sales	74,100	61,000	133,500	113,700
Operating income/(loss)	18,900	14,900	32,500	25,900
Total assets	282,800		282,800		265,700
Operating Segments | Corporate And Eliminations
Segment Reporting Information
Total assets	61,600		61,600		$ 71,200
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	(20,000)	(13,100)	(31,800)	(13,100)
Operating income/(loss)	(14,700)	(17,100)	(30,000)	(31,000)
United States & Canada | Water Systems
Segment Reporting Information
Net sales	93,800	87,400	174,600	159,100
United States & Canada | Distribution
Segment Reporting Information
Net sales	79,500	59,100	135,700	59,100
United States & Canada | Fueling Systems
Segment Reporting Information
Net sales	38,500	36,100	71,300	65,600
United States & Canada | Intersegment Sales | Water Systems
Segment Reporting Information
Net sales	20,000	13,100	31,800	13,100
Latin America | Water Systems
Segment Reporting Information
Net sales	29,000	31,000	58,100	64,000
EMEA | Water Systems
Segment Reporting Information
Net sales	48,500	45,100	97,800	86,500
Asia Pacific | Water Systems
Segment Reporting Information
Net sales	19,100	21,700	39,900	43,200
All Other | Fueling Systems
Segment Reporting Information
Net sales	$ 35,600	$ 24,900	$ 62,200	$ 48,100