SEGMENT INFORMATION (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Oct. 01, 2016	Sep. 30, 2017	Oct. 01, 2016	Dec. 31, 2016
Segment Reporting Information
Net sales	$ 311,113	$ 239,755	$ 836,714	$ 710,266
Operating income/(loss)	31,847	31,811	84,561	85,561
Total assets	1,179,493		1,179,493		$ 1,039,905
Water Systems
Segment Reporting Information
Net sales	179,500	182,000	532,500	545,400
Distribution
Segment Reporting Information
Net sales	68,100	0	127,200	0
Fueling Systems
Segment Reporting Information
Net sales	63,500	57,800	177,100	164,900
Operating Segments | Water Systems
Segment Reporting Information
Net sales	196,500	182,000	567,100	545,400
Operating income/(loss)	28,300	30,000	82,600	85,600
Total assets	699,000		699,000		671,500
Operating Segments | Distribution
Segment Reporting Information
Net sales	68,100	0	127,200	0
Operating income/(loss)	2,000	0	5,600	0
Total assets	158,800		158,800		0
Operating Segments | Fueling Systems
Segment Reporting Information
Net sales	63,500	57,800	178,100	164,900
Operating income/(loss)	17,100	15,200	43,000	40,900
Total assets	260,900		260,900		251,100
Operating Segments | Corporate And Eliminations
Segment Reporting Information
Total assets	60,800		60,800		$ 117,300
Intersegment Sales | Water Systems
Segment Reporting Information
Net sales	17,000	0	34,700	0
Intersegment Sales | Distribution
Segment Reporting Information
Net sales	0	0	0	0
Intersegment Sales | Fueling Systems
Segment Reporting Information
Net sales	0	0	1,000	0
Corporate And Eliminations
Segment Reporting Information
Net sales	(17,000)	0	(35,700)	0
Operating income/(loss)	$ (15,600)	$ (13,400)	$ (46,600)	$ (40,900)