XML 49 R40.htm IDEA: XBRL DOCUMENT v3.25.2

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Property and Equipment, net (Details)	Mar. 31, 2025
Minimum | Property and buildings
PROPERTY, PLANT AND EQUIPMENT, NET
Estimated useful lives (in years)	20 years
Minimum | Machinery and equipment
PROPERTY, PLANT AND EQUIPMENT, NET
Estimated useful lives (in years)	3 years
Minimum | Automobiles
PROPERTY, PLANT AND EQUIPMENT, NET
Estimated useful lives (in years)	3 years
Minimum | Office and electric equipment
PROPERTY, PLANT AND EQUIPMENT, NET
Estimated useful lives (in years)	3 years
Maximum | Property and buildings
PROPERTY, PLANT AND EQUIPMENT, NET
Estimated useful lives (in years)	40 years
Maximum | Machinery and equipment
PROPERTY, PLANT AND EQUIPMENT, NET
Estimated useful lives (in years)	10 years
Maximum | Automobiles
PROPERTY, PLANT AND EQUIPMENT, NET
Estimated useful lives (in years)	5 years
Maximum | Office and electric equipment
PROPERTY, PLANT AND EQUIPMENT, NET
Estimated useful lives (in years)	5 years

X

- 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 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 7A
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478964/842-20-50-7A

+ Details

Name:	us-gaap_PropertyPlantAndEquipmentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

+ References

No definition available.

+ Details

Name:	us-gaap_PropertyPlantAndEquipmentUsefulLife
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	instant

X

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_LandAndBuildingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_MachineryAndEquipmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_AutomobilesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=bgm_OfficeAndElectricEquipmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: