Allowance for Loan Loss (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Financing Receivable, Allowance for Credit Losses	$ 4,808	$ 4,732	$ 4,790	$ 4,757
Financing Receivable, Allowance for Credit Losses, Charge-offs	(1)	(39)	(16)	(97)
Financing Receivable, Allowance for Credit Losses, Recoveries	44	57	77	90
Financing Receivable Allowance For Credit Losses Net Chargeoffs Recoveries	43	18	61	(7)
Provision for loan losses	0	0	0	0
Financing Receivable, Allowance for Credit Losses	4,851	4,750	4,851	4,750
Commercial and Industrial Loans [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Financing Receivable, Allowance for Credit Losses	686	724	778	653
Financing Receivable, Allowance for Credit Losses, Charge-offs	0	0	0	(52)
Financing Receivable, Allowance for Credit Losses, Recoveries	6	32	24	46
Financing Receivable Allowance For Credit Losses Net Chargeoffs Recoveries	6	32	24	(6)
Provision for loan losses	34	(156)	(76)	(47)
Financing Receivable, Allowance for Credit Losses	726	600	726	600
Construction And Land Development Loans [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Financing Receivable, Allowance for Credit Losses	773	670	700	734
Financing Receivable, Allowance for Credit Losses, Charge-offs	0	0	0	0
Financing Receivable, Allowance for Credit Losses, Recoveries	0	0	0	0
Financing Receivable Allowance For Credit Losses Net Chargeoffs Recoveries	0	0	0	0
Provision for loan losses	8	117	81	53
Financing Receivable, Allowance for Credit Losses	781	787	781	787
Commercial Real Estate Loans, Total [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Financing Receivable, Allowance for Credit Losses	2,251	2,119	2,218	2,126
Financing Receivable, Allowance for Credit Losses, Charge-offs	0	(39)	0	(39)
Financing Receivable, Allowance for Credit Losses, Recoveries	1	0	1	0
Financing Receivable Allowance For Credit Losses Net Chargeoffs Recoveries	1	(39)	1	(39)
Provision for loan losses	35	117	68	110
Financing Receivable, Allowance for Credit Losses	2,287	2,197	2,287	2,197
Residential Real Estate Loans, Total [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Financing Receivable, Allowance for Credit Losses	930	1,053	946	1,071
Financing Receivable, Allowance for Credit Losses, Charge-offs	0	0	0	(4)
Financing Receivable, Allowance for Credit Losses, Recoveries	33	17	47	33
Financing Receivable Allowance For Credit Losses Net Chargeoffs Recoveries	33	17	47	29
Provision for loan losses	(59)	(53)	(89)	(83)
Financing Receivable, Allowance for Credit Losses	904	1,017	904	1,017
Consumer Installment and Revolving Loans [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Financing Receivable, Allowance for Credit Losses	168	166	148	173
Financing Receivable, Allowance for Credit Losses, Charge-offs	(1)	0	(16)	(2)
Financing Receivable, Allowance for Credit Losses, Recoveries	4	8	5	11
Financing Receivable Allowance For Credit Losses Net Chargeoffs Recoveries	3	8	(11)	9
Provision for loan losses	(18)	(25)	16	(33)
Financing Receivable, Allowance for Credit Losses	$ 153	$ 149	$ 153	$ 149

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

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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
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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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- 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_
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Balance Type:	debit
Period Type:	duration

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