Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 30
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=109124213&loc=d3e6613-128477

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 30
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=109124213&loc=d3e6578-128477

Name:	us-gaap_BusinessCombinationConsiderationTransferred1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

General - Additional Information (Details) - USD ($) $ in Millions		3 Months Ended
	May 04, 2018	Sep. 30, 2018	Jun. 30, 2018	Sep. 30, 2017
Hebna
General [Line Items]
Total consideration recorded	$ 6.0		$ 3.0
Aegion South Africa Proprietary Limited
General [Line Items]
Ownership percentage by parent				60.00%
Ownership percentage by noncontrolling owners				40.00%
Forecast \| Hebna
General [Line Items]
Total consideration recorded		$ 3.0
OMAN \| Co-venturer [Member]
General [Line Items]
Purchase price paid, percentage	50.00%
Ownership percentage by parent			51.00%