QUARTERLY FINANCIAL INFORMATION (unaudited) (Details) - USD ($) $ / shares in Units, $ 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, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Quarterly Financial Information Disclosure [Abstract]
Total revenue	$ 311,000	$ 308,000	$ 311,200	$ 285,900	$ 265,700	$ 251,900	$ 250,700	$ 238,500	$ 222,300	$ 230,000	$ 256,200	$ 253,600	$ 1,216,197	$ 1,006,782	$ 962,092
Gross profit	86,600	84,100	85,100	76,400	71,200	67,000	68,900	64,500	60,600	63,800	71,600	68,800	332,208	271,581	264,802
Net income (loss)	11,100	8,400	11,600	4,500	6,600	3,000	4,100	3,100	7,100	100	5,100	(5,200)	35,521	16,529	7,151
Net income attributable to DXP Enterprises, Inc.	$ 11,100	$ 8,400	$ 11,600	$ 4,600	$ 6,600	$ 2,900	$ 4,000	$ 3,000	$ 7,400	$ 200	$ 5,100	$ (5,100)	$ 35,632	$ 16,888	$ 7,702
Basic (in dollars per share)	$ 0.63	$ 0.48	$ 0.66	$ 0.26	$ 0.38	$ 0.17	$ 0.24	$ 0.18	$ 0.44	$ 0.02	$ 0.36	$ (0.36)	$ 2.02	$ 0.97	$ 0.51
Diluted (in dollars per share)	$ 0.60	$ 0.46	$ 0.63	$ 0.25	$ 0.37	$ 0.16	$ 0.23	$ 0.17	$ 0.42	$ 0.02	$ 0.34	$ (0.36)	$ 1.94	$ 0.93	$ 0.49