QUARTERLY FINANCIAL INFORMATION (Unaudited) (Details) (USD $)	3 Months Ended																					12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014		Jun. 30, 2014		Mar. 31, 2014		Dec. 31, 2013	Sep. 30, 2013		Jun. 30, 2013		Mar. 31, 2013		Dec. 31, 2012	Sep. 30, 2012		Jun. 30, 2012		Mar. 31, 2012		Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Quarterly Financial Information [Line Items]
Sales	$ 382,600,000	$ 387,000,000	[1]	$ 381,600,000	[1]	$ 348,500,000	[1]	$ 313,800,000	$ 329,700,000	[1]	$ 307,900,000	[1]	$ 290,100,000	[1]	$ 293,000,000	$ 289,900,000	[1]	$ 261,900,000	[1]	$ 252,300,000	[1]	$ 1,499,662,000	$ 1,241,510,000	$ 1,097,110,000
Gross profit	106,700,000	113,400,000	[1]	111,000,000	[1]	101,700,000	[1]	94,600,000	97,100,000	[1]	91,500,000	[1]	89,100,000	[1]	87,500,000	83,500,000	[1]	76,600,000	[1]	71,500,000	[1]	432,840,000	372,345,000	319,091,000
Impairment expense	117,600,000	0	[1]	0	[1]	0	[1]															117,569,000	0	0
Net income (loss)	(88,100,000)	17,000,000	[1]	14,900,000	[1]	10,900,000	[1]	16,900,000	16,400,000	[1]	13,700,000	[1]	13,200,000	[1]	14,100,000	13,100,000	[1]	12,200,000	[1]	11,600,000	[1]	(45,238,000)	60,237,000	50,985,000
Earnings (loss) per share - basic (in dollars per share)	$ (6.09)	$ 1.16	[1]	$ 1.01	[1]	$ 0.74	[1]	$ 1.17	$ 1.13	[1]	$ 0.95	[1]	$ 0.92	[1]	$ 0.98	$ 0.91	[1]	$ 0.84	[1]	$ 0.81	[1]	$ (3.10)	$ 4.17	$ 3.54
Earnings (loss) per share - diluted (in dollars per share)	$ (6.09)	$ 1.10	[1]	$ 0.96	[1]	$ 0.70	[1]	$ 1.10	$ 1.07	[1]	$ 0.90	[1]	$ 0.87	[1]	$ 0.92	$ 0.86	[1]	$ 0.80	[1]	$ 0.77	[1]	$ (3.10)	$ 3.94	$ 3.35
Increase in amortization expense	1,000,000
Previously Reported [Member]
Quarterly Financial Information [Line Items]
Sales		387,000,000		381,600,000		348,500,000
Gross profit		113,400,000		111,000,000		101,700,000
Net income (loss)		17,600,000		15,500,000		11,600,000
Earnings (loss) per share - basic (in dollars per share)		$ 1.20		$ 1.06		$ 0.79
Earnings (loss) per share - diluted (in dollars per share)		$ 1.14		$ 1.00		$ 0.75
Adjusted [Member]
Quarterly Financial Information [Line Items]
Sales		387,000,000		381,600,000		348,500,000
Gross profit		113,400,000		111,000,000		101,700,000
Net income (loss)		$ 17,000,000		$ 14,800,000		$ 10,900,000
Earnings (loss) per share - basic (in dollars per share)		$ 1.16		$ 1.01		$ 0.74
Earnings (loss) per share - diluted (in dollars per share)		$ 1.10		$ 0.96		$ 0.70

[1] During the fourth quarter of 2014, DXP finalized its purchase accounting for customer relationships for the acquisition of B27 and amortized the customer relationships on an accelerated basis. The revision increased amortization expense by $1.0 million per quarter.