XML 161 R47.htm IDEA: XBRL DOCUMENT
v3.25.2

SECURITIES AND OTHER INVESTMENTS (Amortized Cost of HTM Securities by Security Type and Credit Rating) (Details) - USD ($) $ in Thousands | Jun. 30, 2025 | Dec. 31, 2024
--- | --- | ---
HTM Securities, Amortized Cost | $ 827,135 | $ 803,851
Moody's AAA/AA/A |  |
HTM Securities, Amortized Cost | 723,697 | 692,671
Moody's BBB/BB/B |  |
HTM Securities, Amortized Cost | 1,133 | 1,144
Moody's Not Rated - Agency |  |
HTM Securities, Amortized Cost | 63,430 | 64,595
Moody's Not Rated - Non-Agency |  |
HTM Securities, Amortized Cost | 38,875 | 45,441
US States and Political Subdivisions Debt Securities [Member] |  |
HTM Securities, Amortized Cost | 730,121 | 697,683
US States and Political Subdivisions Debt Securities [Member] | Moody's AAA/AA/A |  |
HTM Securities, Amortized Cost | 719,386 | 686,923
US States and Political Subdivisions Debt Securities [Member] | Moody's BBB/BB/B |  |
HTM Securities, Amortized Cost | 1,133 | 1,144
US States and Political Subdivisions Debt Securities [Member] | Moody's Not Rated - Agency |  |
HTM Securities, Amortized Cost | 0 | 0
US States and Political Subdivisions Debt Securities [Member] | Moody's Not Rated - Non-Agency |  |
HTM Securities, Amortized Cost | 9,602 | 9,616
Corporate Bond Securities [Member] |  |
HTM Securities, Amortized Cost | 2,978 | 3,322
Corporate Bond Securities [Member] | Moody's AAA/AA/A |  |
HTM Securities, Amortized Cost | 0 | 0
Corporate Bond Securities [Member] | Moody's BBB/BB/B |  |
HTM Securities, Amortized Cost | 0 | 0
Corporate Bond Securities [Member] | Moody's Not Rated - Agency |  |
HTM Securities, Amortized Cost | 0 | 0
Corporate Bond Securities [Member] | Moody's Not Rated - Non-Agency |  |
HTM Securities, Amortized Cost | 2,978 | 3,322
Collateralized Mortgage-Backed Securities [Member] |  |
HTM Securities, Amortized Cost | 94,036 | 102,846
Collateralized Mortgage-Backed Securities [Member] | Moody's AAA/AA/A |  |
HTM Securities, Amortized Cost | 4,311 | 5,748
Collateralized Mortgage-Backed Securities [Member] | Moody's BBB/BB/B |  |
HTM Securities, Amortized Cost | 0 | 0
Collateralized Mortgage-Backed Securities [Member] | Moody's Not Rated - Agency |  |
HTM Securities, Amortized Cost | 63,430 | 64,595
Collateralized Mortgage-Backed Securities [Member] | Moody's Not Rated - Non-Agency |  |
HTM Securities, Amortized Cost | $ 26,295 | $ 32,503

X
- Definition Amount excluding accrued interest, after allowance for credit loss, of investment in debt security measured at amortized cost (held-to-maturity). + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479344/326-20-45-1 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481800/320-10-50-5 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (f) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481800/320-10-50-5 + Details
Name: | us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestAfterAllowanceForCreditLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | srt_CreditRatingMoodysAxis=aub_MoodysAaaAaRatingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_CreditRatingMoodysAxis=aub_MoodySBbbBbBRatingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_CreditRatingMoodysAxis=aub_MoodySNotRatedAgencyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_CreditRatingMoodysAxis=aub_MoodySNotRatedNonAgencyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_USStatesAndPoliticalSubdivisionsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_CorporateBondSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_MortgageBackedSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |