SUMMARY OF SIGNIFICANT ACCOUNTING AND BUSINESS POLICIES - Out-of-Period Items (Details) $ in Millions	3 Months Ended
Dec. 31, 2017 USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Deferred tax liability true up	$ (2.2)

Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to foreign acquisition deferred tax liability pursuant to Tax Cuts and Jobs Act of 2017.

No definition available.

Name:	dxpe_EffectiveIncomeTaxRateReconciliationTaxCutsAndJobsActOf2017ForeignAcquisitionDeferredTaxLiability
Namespace Prefix:	dxpe_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration