SEGMENT AND GEOGRAPHIC INFORMATION (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information
Revenue from Contract with Customer, Excluding Assessed Tax	$ 316,600	$ 341,900	$ 344,000	$ 295,600	$ 288,200	$ 311,100	$ 305,300	$ 220,300	$ 1,298,129	$ 1,124,909	$ 949,856
Operating income (loss)									131,994	107,228	112,070
Total assets	1,182,365				1,185,353				1,182,365	1,185,353	1,039,900
Depreciation									29,700	29,900	27,100
Long-lived assets	593,800				587,300				593,800	587,300	551,500
Amortization									8,900	8,600	8,400
Capital Expenditures Incurred In Year, Paid And Not Paid									23,400	33,400	37,600
United States
Segment Reporting Information
Revenue from Contract with Customer, Excluding Assessed Tax									738,200	596,600	446,900
Long-lived assets	372,600				326,100				372,600	326,100	349,200
Foreign
Segment Reporting Information
Revenue from Contract with Customer, Excluding Assessed Tax									559,900	528,300	503,000
Long-lived assets	221,200				261,200				221,200	261,200	202,300
Operating Segments | Water Systems
Segment Reporting Information
Revenue from Contract with Customer, Excluding Assessed Tax									796,500	743,300	723,200
Operating income (loss)									112,900	102,000	108,200
Total assets	679,700				695,400				679,700	695,400	671,500
Depreciation									20,400	20,900	19,500
Amortization									6,500	6,200	6,400
Capital Expenditures Incurred In Year, Paid And Not Paid									18,200	19,100	31,800
Operating Segments | Distribution
Segment Reporting Information
Revenue from Contract with Customer, Excluding Assessed Tax									269,600	176,700	0
Operating income (loss)									3,400	3,700	0
Total assets	165,100				153,100				165,100	153,100	0
Depreciation									2,200	1,300	0
Amortization									500	400	0
Capital Expenditures Incurred In Year, Paid And Not Paid									2,000	1,100	0
Operating Segments | Fueling Systems
Segment Reporting Information
Revenue from Contract with Customer, Excluding Assessed Tax									288,200	245,700	226,700
Operating income (loss)									70,400	60,000	56,300
Total assets	275,700				265,700				275,700	265,700	251,100
Depreciation									2,200	2,200	2,300
Amortization									1,800	1,900	1,900
Capital Expenditures Incurred In Year, Paid And Not Paid									2,200	11,000	2,100
Operating Segments | Latin America | Water Systems
Segment Reporting Information
Revenue from Contract with Customer, Excluding Assessed Tax									120,900	130,000	127,500
Operating Segments | United States & Canada | Water Systems
Segment Reporting Information
Revenue from Contract with Customer, Excluding Assessed Tax									354,100	308,500	343,100
Operating Segments | United States & Canada | Distribution
Segment Reporting Information
Revenue from Contract with Customer, Excluding Assessed Tax									269,600	176,700	0
Operating Segments | United States & Canada | Fueling Systems
Segment Reporting Information
Revenue from Contract with Customer, Excluding Assessed Tax									160,500	145,400	139,300
Operating Segments | EMEA | Water Systems
Segment Reporting Information
Revenue from Contract with Customer, Excluding Assessed Tax									184,300	177,700	167,300
Operating Segments | Asia Pacific | Water Systems
Segment Reporting Information
Revenue from Contract with Customer, Excluding Assessed Tax									81,000	86,300	85,300
Operating Segments | AllOther | Fueling Systems
Segment Reporting Information
Revenue from Contract with Customer, Excluding Assessed Tax									127,700	100,300	87,400
Intersegment Sales | Water Systems
Segment Reporting Information
Revenue from Contract with Customer, Excluding Assessed Tax									56,200	40,800	0
Intersegment Sales | Distribution
Segment Reporting Information
Revenue from Contract with Customer, Excluding Assessed Tax									0	0	0
Intersegment Sales | Fueling Systems
Segment Reporting Information
Revenue from Contract with Customer, Excluding Assessed Tax									0	0	0
Intersegment Eliminations/Other
Segment Reporting Information
Revenue from Contract with Customer, Excluding Assessed Tax									(56,200)	(40,800)	0
Operating income (loss)									(54,700)	(58,500)	(52,400)
Intersegment Eliminations/Other | Intersegment Eliminations/Other
Segment Reporting Information
Total assets	$ 61,900				$ 71,200				61,900	71,200	117,300
Depreciation									4,900	5,500	5,300
Amortization									100	100	100
Capital Expenditures Incurred In Year, Paid And Not Paid									$ 1,000	$ 2,200	$ 3,700