Business combination payment through cash or common stock.

No definition available.

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Namespace Prefix:	meg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- 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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 805
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479907/805-20-50-5

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

Percentage of voting equity interests acquired at the acquisition date in the business combination.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479328/805-10-50-2

+ Details

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Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

This element represents acquisition-related costs incurred to effect a business combination which costs have been expensed during the period. Such costs include finder's fees; advisory, legal, accounting, valuation, and other professional or consulting fees; general administrative costs, including the costs of maintaining an internal acquisitions department; and may include costs of registering and issuing debt and equity securities.

+ References

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-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 25
-Paragraph 23
-Publisher FASB
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Balance Type:	debit
Period Type:	duration

- Definition

Amount of equity interests of the acquirer, including instruments or interests issued or issuable in consideration for the business combination.

+ References

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-Name Accounting Standards Codification
-Section 30
-Paragraph 8
-SubTopic 30
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+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

For contingent consideration arrangements recognized in connection with a business combination, this element represents an estimate of the high-end of the potential range (undiscounted) of the consideration which may be paid.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
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-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (c)(3)
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-URI https://asc.fasb.org//1943274/2147479581/805-30-50-1

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

This element represents the amount of earnings or loss of the acquiree since the acquisition date included in the consolidated income statement for the reporting period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
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-SubTopic 10
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-Subparagraph (h)(1)
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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

This element represents the amount of revenue of the acquiree since the acquisition date included in the consolidated income statement for the reporting period.

+ References

+ Details

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

- Definition

Amount of increase (decrease) from adjustments after acquisition date under purchase accounting of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 350
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (g)
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 805
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (b)(1)
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- Details

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- Details

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- Details

Name:	us-gaap_BusinessAcquisitionAxis=meg_TwoDotConsultingLlcMember
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- Details

Name:	us-gaap_BusinessAcquisitionAxis=meg_GreenpathEnergyLtdMember
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- Details

Name:	us-gaap_BusinessAcquisitionAxis=meg_MatrixMember
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- Details

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- Details

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Business Acquisitions - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Feb. 28, 2024	Jan. 31, 2024	Jul. 31, 2023	Jun. 30, 2023	May 31, 2023	Feb. 28, 2023
Business Acquisition [Line Items]
Transaction costs related to business combinations	$ 2,525	$ 775
Common Stock	6,580
Business combination, paid in cash	59,307
Acquisitions measurement period adjustments	300
EPIC
Business Acquisition [Line Items]
Percentage of interests acquired				100.00%
Common Stock	4,748
Business combination, paid in cash	19,914
EAI
Business Acquisition [Line Items]
Percentage of interests acquired								100.00%
2DOT
Business Acquisition [Line Items]
Percentage of interests acquired			100.00%
Common Stock	1,832
Business combination, paid in cash	39,393
GreenPath
Business Acquisition [Line Items]
Percentage of interests acquired							100.00%
Matrix
Business Acquisition [Line Items]
Percentage of interests acquired						100.00%
Vandrensning
Business Acquisition [Line Items]
Percentage of interests acquired					100.00%
EnvStd and IAG \| 2026 Earn Out
Business Acquisition [Line Items]
Payment through cash or common stock	13,100
Common Stock	13,100
Business combination, earn-out payment, maximum	40,400
Business combination, paid in cash	14,200
EPIC, Two Dot
Business Acquisition [Line Items]
Revenue	3,900
Pre-tax income (loss)	$ 1,300
Frontier, EAI, GreenPath and Matrix
Business Acquisition [Line Items]
Revenue		1,000
Pre-tax income (loss)		$ 100