Inventories - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2018	Jun. 30, 2018	Jun. 30, 2017
Lower Of Cost Or Net Realizable Value Adjustment	$ 34,700	$ 30,906	$ 0
Lower Of Cost Or Net Realizable Value Adjustment Gross	17,100
Airgas [Member]
Lower Of Cost Or Net Realizable Value Adjustment Gross	$ 17,600

Gross Amount of expense related to lower of cost or net realizable value adjustment incurred during the year.

No definition available.

Name:	hdsn_LowerOfCostOrNetRealizableValueAdjustmentGross
Namespace Prefix:	hdsn_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration