SEGMENT REPORTING - Schedule of Financial Information of Company's Segments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Segment Reporting Information [Line Items]
Sales	$ 513,724	$ 472,935	$ 1,488,975	$ 1,331,126
Other expenses
Income from operations	43,698	39,608	130,199	106,091
Interest expense	14,894	15,716	44,298	46,644
Other income, net	(648)	160	(2,320)	(2,844)
Income before income taxes	29,452	23,732	88,221	62,291
Selling, general and administrative expenses	117,561	106,502	339,138	301,694
Operating Segments
Segment Reporting Information [Line Items]
Sales	513,724	472,935	1,488,975	1,331,126
Operating expenses	435,599	400,319	1,264,951	1,137,700
Other expenses
Depreciation	2,811	2,365	7,647	6,821
Amortization of finance lease assets	1,742	1,110	4,846	3,231
Other	29,874	29,533	81,332	77,283
Income from operations	43,698	39,608	130,199	106,091
Interest expense	14,894	15,716	44,298	46,644
Other income, net	(648)	160	(2,320)	(2,844)
Income before income taxes	29,452	23,732	88,221	62,291
Capital expenditures	6,740	3,954	37,000	15,673
Corporate
Segment Reporting Information [Line Items]
Sales	0	0	0	0
Operating expenses	0	0	0	0
Other expenses
Depreciation	1,034	702	2,423	1,916
Amortization of finance lease assets	443	87	1,151	236
Other	29,874	29,533	81,332	77,283
Income from operations	(31,351)	(30,322)	(84,906)	(79,435)
Interest expense	14,894	15,716	44,298	46,644
Other income, net	(648)	160	(2,320)	(2,844)
Income before income taxes	(45,597)	(46,198)	(126,884)	(123,235)
Capital expenditures	4,722	2,000	30,998	10,007
Selling, general and administrative expenses	24,500	24,300	65,200	63,000
Amortization of intangible assets	5,400	5,200	16,100	14,300
Total Reportable Segments | Operating Segments
Segment Reporting Information [Line Items]
Sales	513,724	472,935	1,488,975	1,331,126
Operating expenses	435,599	400,319	1,264,951	1,137,700
Other expenses
Depreciation	1,777	1,663	5,224	4,905
Amortization of finance lease assets	1,299	1,023	3,695	2,995
Other	0	0	0	0
Income from operations	75,049	69,930	215,105	185,526
Interest expense	0	0	0	0
Other income, net	0	0	0	0
Income before income taxes	75,049	69,930	215,105	185,526
Capital expenditures	2,018	1,954	6,002	5,666
Service Center
Segment Reporting Information [Line Items]
Sales	350,179	316,831	1,016,985	911,783
Service Center | Operating Segments
Segment Reporting Information [Line Items]
Sales	350,179	316,831	1,016,985	911,783
Operating expenses	296,817	269,034	862,649	776,565
Other expenses
Depreciation	995	807	2,864	2,334
Amortization of finance lease assets	1,021	835	2,911	2,554
Other	0	0	0	0
Income from operations	51,346	46,155	148,561	130,330
Interest expense	0	0	0	0
Other income, net	0	0	0	0
Income before income taxes	51,346	46,155	148,561	130,330
Capital expenditures	936	1,034	3,434	3,089
Innovative Pumping Solutions
Segment Reporting Information [Line Items]
Sales	100,551	89,825	280,273	225,417
Innovative Pumping Solutions | Operating Segments
Segment Reporting Information [Line Items]
Sales	100,551	89,825	280,273	225,417
Operating expenses	81,147	70,614	226,832	183,980
Other expenses
Depreciation	774	848	2,336	2,547
Amortization of finance lease assets	231	156	657	347
Other	0	0	0	0
Income from operations	18,399	18,207	50,448	38,543
Interest expense	0	0	0	0
Other income, net	0	0	0	0
Income before income taxes	18,399	18,207	50,448	38,543
Capital expenditures	1,082	920	2,568	2,564
Supply Chain Services
Segment Reporting Information [Line Items]
Sales	62,994	66,279	191,717	193,926
Supply Chain Services | Operating Segments
Segment Reporting Information [Line Items]
Sales	62,994	66,279	191,717	193,926
Operating expenses	57,635	60,671	175,470	177,155
Other expenses
Depreciation	8	8	24	24
Amortization of finance lease assets	47	32	127	94
Other	0	0	0	0
Income from operations	5,304	5,568	16,096	16,653
Interest expense	0	0	0	0
Other income, net	0	0	0	0
Income before income taxes	5,304	5,568	16,096	16,653
Capital expenditures	$ 0	$ 0	$ 0	$ 13