Number of claims filed industry-wide.

No definition available.

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- Definition

Represents the number of shareholder derivative actions that were filed.

+ References

No definition available.

+ Details

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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- Definition

Amount of loss contingency liability.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=121557415&loc=d3e14326-108349

+ Details

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Balance Type:	credit
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- Definition

The amount of loss pertaining to the specified contingency that was charged against earnings in the period, including the effects of revisions in previously reported estimates.

+ References

+ Details

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- Definition

Number of defendants named in a legal action.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
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- Details

Name:	srt_LitigationCaseAxis=asrt_SecuritiesClassActionLawsuitMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_LitigationCaseAxis=asrt_MultidistrictOpioidLitigationMember
Namespace Prefix:
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Balance Type:
Period Type:

COMMITMENTS AND CONTINGENCIES - Legal Matters (Details) $ in Millions		3 Months Ended	9 Months Ended
	Aug. 23, 2017 defendant action	Sep. 30, 2021 USD ($) case	Sep. 30, 2021 USD ($) case	Dec. 31, 2020 USD ($)
Legal matters
Legal contingency accrual		$ 3.6	$ 3.6	$ 0.0
(Gain) loss contingency provision		$ (0.8)	$ 10.6
Securities Class Action Lawsuit and Related Matters
Legal matters
Number of defendants \| defendant	2
Number of shareholder derivative actions filed \| action	5
Multidistrict Opioid Litigation
Legal matters
Number of industry-wide opioid litigation cases (more than) \| case		2,000	2,000