XML 60 R46.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Income taxes - Additional Information (Detail) - USD ($) $ in Thousands | 3 Months Ended | 12 Months Ended
--- | --- | ---
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 | Dec. 31, 2015
Income Tax [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Operating Loss Carry forwards Expiration Period |  |  |  |  |  |  |  |  |  |  | 2024 |  |  |  |
Income Tax Expense (Benefit) | $ (7,389) | [1] | $ (652) | $ 5,314 | $ 3,574 | $ (1,071) | $ 2,933 | $ 2,962 | $ 1,804 |  | $ 847 | [2] | $ 6,628 | [2] | $ 2,944
Operating Loss Carryforwards | 5,400 |  |  |  |  |  |  |  |  |  | $ 5,400 |  |  |  |
Operating Loss Carryforwards, Limitations on Use |  |  |  |  |  |  |  |  |  |  | All of the Companys remaining $4.1 million of NOLs are subject to annual limitations of $1.3 million. |  |  |  |
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent |  |  |  |  |  |  |  |  |  |  | 35.00% |  | 35.00% |  | 34.00%
Scenario, Plan [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Tax [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent |  |  |  |  |  |  |  |  |  | 21.00% |  |  |  |  |
State and Local Jurisdiction [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Tax [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Operating Loss Carryforwards | $ 2,600 |  |  |  |  |  |  |  |  |  | $ 2,600 |  |  |  |
[1] | As discussed previously, the fourth quarter 2017 results include the results of ARI subsequent to the acquisition on October 10, 2017.
[2] | The sum of the net earnings per share may not add up to the full year amount due to rounding and because the quarterly calculations are based on varying numbers of shares outstanding.

X
- References No definition available. + Details
Name: | hdsn_IncomeTaxLineItems
Namespace Prefix: | hdsn_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Expiration period of each operating loss carryforward included in operating loss carryforward. + References No definition available. + Details
Name: | hdsn_OperatingLossCarryForwardsExpirationPeriod
Namespace Prefix: | hdsn_
Data Type: | xbrli:gYearItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of domestic federal statutory tax rate applicable to pretax income (loss). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 12 -URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32687-109319 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SAB TOPIC 6.I) -URI http://asc.fasb.org/extlink&oid=34349781&loc=d3e330036-122817 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 13 -URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32698-109319 + Details
Name: | us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 9 -Subparagraph (a),(b) -URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32639-109319 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08.(h)) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690 + Details
Name: | us-gaap_IncomeTaxExpenseBenefit
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of operating loss carryforward, before tax effects, available to reduce future taxable income under enacted tax laws. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32559-109319 + Details
Name: | us-gaap_OperatingLossCarryforwards
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition A description of the limitations on the use of all operating loss carryforwards available to reduce future taxable income. + References No definition available. + Details
Name: | us-gaap_OperatingLossCarryforwardsLimitationsOnUse
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_StatementScenarioAxis=us-gaap_ScenarioPlanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_IncomeTaxAuthorityAxis=us-gaap_StateAndLocalJurisdictionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |