Defined contribution plan, service period.

No definition available.

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- Definition

Defined contributions plan contributions by employer.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Number of contributory defined investment plan.

+ References

No definition available.

+ Details

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Namespace Prefix:	aobc_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of contributions made by the employer to defined benefit plans.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (d)(5)(ii)
-URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e1928-114920

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 60
-Section 35
-Paragraph 123
-Subparagraph B
-URI http://asc.fasb.org/extlink&oid=64937487&loc=d3e36068-114959

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 30
-Section 35
-Paragraph 63
-Subparagraph B
-URI http://asc.fasb.org/extlink&oid=64937038&loc=d3e12551-114930

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (b)(3)
-URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e1928-114920

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (d)(5)(iv)(01)
-URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e1928-114920

+ Details

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

- Definition

Amount of employer's best estimate of contributions expected to be paid to the plan in the current remaining fiscal period.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- 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

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- Definition

Percentage of employees' gross pay for which the employer contributes a matching contribution to a defined contribution plan.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
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Balance Type:	na
Period Type:	duration

- Definition

Percentage employer matches of the employee's percentage contribution matched.

+ References

No definition available.

+ Details

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Period Type:	duration

- Definition

Maximum percentage of employee gross pay the employee may contribute to a defined contribution plan.

+ References

No definition available.

+ Details

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Balance Type:	na
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- Definition

Description of the terms and benefits provided by the employer's defined contribution plans. A defined contribution plan provides benefits in return for services rendered, provides an individual account for each participant, and has terms that specify how contributions to the individual's account are to be determined rather than the amount of benefits the individual is to receive. Under a defined contribution pension plan, the benefits a participant will receive depend solely on the amount contributed to the participant's account, the returns earned on investments of those contributions, and forfeitures of other participants' benefits that may be allocated to such participant's account. A description of the plan(s) including employee groups covered, the basis for determining contributions, and the nature and effects of significant matters affecting comparability of information for all periods presented.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 70
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=49170846&loc=d3e28014-114942

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Defined Contribution Plan
-URI http://asc.fasb.org/extlink&oid=49180617

+ Details

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- Details

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Employer Sponsored Benefit Plans - Additional Information (Detail) $ in Millions	12 Months Ended
	Apr. 30, 2017 USD ($) InvestmentPlan	Apr. 30, 2016 USD ($)	Apr. 30, 2015 USD ($)
Contributory Defined Investment Plan
Defined Contribution Plan Disclosure [Line Items]
Number of contributory defined investment plan \| InvestmentPlan	2
Defined contribution plan, employee contribution percentage	100.00%
Defined contribution plan, matching contribution percentage	6.00%
Deferred compensation plan description	We offer two contributory defined investment plans covering substantially all employees, subject to service requirements. Employees may contribute up to 100% of their annual pay, depending on the plan. We generally make discretionary matching contributions of up to 50% of the first 6% of employee contributions to the plan.
Employer contribution to defined benefit plan	$ 2.7	$ 2.4	$ 2.3
Contributory Defined Investment Plan \| Maximum
Defined Contribution Plan Disclosure [Line Items]
Defined contribution plan, matching contribution percentage of match	50.00%
Non-Contributory Profit Sharing Plan
Defined Contribution Plan Disclosure [Line Items]
Defined contribution plan service period	1 year
Employer contribution to defined benefit plan		$ 11.5	$ 6.2
Defined contribution plan expected contribution	$ 13.0