Allowance for Loan Loss (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Financing Receivable, Allowance for Credit Losses	$ 4,790	$ 4,757
Financing Receivable, Allowance for Credit Losses, Charge-offs	(15)	(58)
Financing Receivable, Allowance for Credit Losses, Recoveries	33	33
Financing Receivable Allowance For Credit Losses Net Chargeoffs Recoveries	18	(25)
Provision for loan losses	0	0
Financing Receivable, Allowance for Credit Losses	4,808	4,732
Commercial and Industrial Loans [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Financing Receivable, Allowance for Credit Losses	778	653
Financing Receivable, Allowance for Credit Losses, Charge-offs	0	(52)
Financing Receivable, Allowance for Credit Losses, Recoveries	18	14
Financing Receivable Allowance For Credit Losses Net Chargeoffs Recoveries	18	(38)
Provision for loan losses	(110)	109
Financing Receivable, Allowance for Credit Losses	686	724
Construction And Land Development Loans [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Financing Receivable, Allowance for Credit Losses	700	734
Financing Receivable, Allowance for Credit Losses, Charge-offs	0	0
Financing Receivable, Allowance for Credit Losses, Recoveries	0	0
Financing Receivable Allowance For Credit Losses Net Chargeoffs Recoveries	0	0
Provision for loan losses	73	(64)
Financing Receivable, Allowance for Credit Losses	773	670
Commercial Real Estate Loans, Total [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Financing Receivable, Allowance for Credit Losses	2,218	2,126
Financing Receivable, Allowance for Credit Losses, Charge-offs	0	0
Financing Receivable, Allowance for Credit Losses, Recoveries	0	0
Financing Receivable Allowance For Credit Losses Net Chargeoffs Recoveries	0	0
Provision for loan losses	33	(7)
Financing Receivable, Allowance for Credit Losses	2,251	2,119
Residential Real Estate Loans, Total [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Financing Receivable, Allowance for Credit Losses	946	1,071
Financing Receivable, Allowance for Credit Losses, Charge-offs	0	(4)
Financing Receivable, Allowance for Credit Losses, Recoveries	14	16
Financing Receivable Allowance For Credit Losses Net Chargeoffs Recoveries	14	12
Provision for loan losses	(30)	(30)
Financing Receivable, Allowance for Credit Losses	930	1,053
Consumer Installment and Revolving Loans [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Financing Receivable, Allowance for Credit Losses	148	173
Financing Receivable, Allowance for Credit Losses, Charge-offs	(15)	(2)
Financing Receivable, Allowance for Credit Losses, Recoveries	1	3
Financing Receivable Allowance For Credit Losses Net Chargeoffs Recoveries	(14)	1
Provision for loan losses	34	(8)
Financing Receivable, Allowance for Credit Losses	$ 168	$ 166

No definition available.

Name:	aubn_FinancingReceivableAllowanceForCreditLossesNetChargeoffsRecoveries
Namespace Prefix:	aubn_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

A valuation allowance for financing receivables that are expected to be uncollectible.

+ References

+ Details

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

- Definition

Amount of recovery of financing receivables doubtful of collection that were previously charged off.

+ References

+ Details

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

- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

+ Details

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

- Definition

Amount of direct write-downs of financing receivables charged against the allowance.

+ References

+ Details

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

- Definition

Amount of expense related loan transactions, lease transactions, credit loss from transactions other than loan and lease transactions, and other loss based on assessment of uncollectability from the counterparty to reduce the account to their net realizable value.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (c)(2)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953423-111524

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04.11)
-URI http://asc.fasb.org/extlink&oid=114873765&loc=SL114874048-224260

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3602-108585

+ Details

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

- Details

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Namespace Prefix:
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- Details

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- Details

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- Details

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