GOODWILL AND OTHER INTANGIBLE ASSETS (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Goodwill [Roll Forward]
Beginning balance	$ 145,788,000	$ 101,764,000
Acquired during the year	39,898,000	44,074,000
Adjustments to prior year estimates	2,424,000	(50,000)
Translation adjustment	0	0
Ending balance	188,110,000	145,788,000	101,764,000
Other Intangibles Assets [Roll Forward]
Balance at beginning of period	63,189,000	43,194,000
Acquired during the year	22,033,000	30,643,000
Adjustments to prior year estimates	(2,424,000)	50,000
Translation adjustment	(1,246,000)	188,000
Amortization	(11,830,000)	(10,886,000)	(6,572,000)
Balance at end of period	69,722,000	63,189,000	43,194,000
Total Goodwill and Intangible Assets [Roll Forward]
Beginning Balance	208,977,000	144,958,000
Acquired during the year	61,931,000	74,717,000
Adjustment to prior year estimates	0	0
Translation adjustment	(1,246,000)	188,000
Amortization	(11,830,000)	(10,886,000)	(6,572,000)
Ending Balance	257,832,000	208,977,000	144,958,000
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	114,132,000	94,888,000
Accumulated amortization	(44,410,000)	(31,699,000)
Carrying amount, net	69,722,000	63,189,000
Amortization expense	11,830,000	10,886,000	6,572,000
The estimated future annual amortization of intangible assets for each of the next five years and thereafter [Abstract]
2014	12,966,000
2015	11,532,000
2016	9,172,000
2017	9,089,000
2018	8,354,000
Thereafter	18,609,000
Vendor Agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	2,496,000	2,496,000
Accumulated amortization	(1,205,000)	(1,081,000)
Carrying amount, net	1,291,000	1,415,000
Weighted average remaining estimated life	11 years 10 months 24 days
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	109,897,000	90,851,000
Accumulated amortization	(42,468,000)	(30,010,000)
Carrying amount, net	67,429,000	60,841,000
Weighted average remaining estimated life	7 years 1 month 6 days
Increase in goodwill	2,300,000
Non-Compete Agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	1,739,000	1,541,000
Accumulated amortization	(737,000)	(608,000)
Carrying amount, net	1,002,000	933,000
Weighted average remaining estimated life	3 years 4 months 24 days
Service Centers [Member]
Goodwill [Roll Forward]
Ending balance	142,714,000	112,670,000
Innovative Pumping Solutions [Member]
Goodwill [Roll Forward]
Ending balance	28,258,000	15,980,000
Supply Chain Services [Member]
Goodwill [Roll Forward]
Ending balance	$ 17,138,000	$ 17,138,000