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v3.21.1

SIGNIFICANT ACCOUNTING POLICIES - Intangible assets (Details) | 12 Months Ended
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Dec. 31, 2020
Software | Minimum |
Finite-Lived Intangible Assets [Line Items] |
Estimated useful lives (in years) | 2 years
Software | Maximum |
Finite-Lived Intangible Assets [Line Items] |
Estimated useful lives (in years) | 10 years
Student populations | Minimum |
Finite-Lived Intangible Assets [Line Items] |
Estimated useful lives (in years) | 1 year 9 months 18 days
Student populations | Maximum |
Finite-Lived Intangible Assets [Line Items] |
Estimated useful lives (in years) | 15 years
Others | Minimum |
Finite-Lived Intangible Assets [Line Items] |
Estimated useful lives (in years) | 1 year 3 months 18 days
Others | Maximum |
Finite-Lived Intangible Assets [Line Items] |
Estimated useful lives (in years) | 10 years

X
- Definition Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References No definition available. + Details
Name: | us-gaap_FiniteLivedIntangibleAssetUsefulLife
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

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

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- Details
Name: | us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=us-gaap_ComputerSoftwareIntangibleAssetMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

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

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- Details
Name: | us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=us-gaap_CustomerRelatedIntangibleAssetsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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- Details
Name: | us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=ambo_OtherMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |