Plan assets of a defined benefit plan, as a percentage of projected benefit obligation.

No definition available.

Name:	us-gaap_DefinedBenefitPlanFundedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

Amount of administrative expenses incurred by a defined contribution plan.

No definition available.

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

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

No definition available.

Name:	us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

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

No definition available.

Name:	us-gaap_DefinedContributionPlanEmployerMatchingContributionPercentOfMatch
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

A portion of the employee's compensation multiplied by a specific percentage.

No definition available.

Name:	zeus_DefinedContributionPlanCompensationPercentageMultiplier
Namespace Prefix:	zeus_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

The vesting period of the employer's matching contributions to a defined contribution plan.

No definition available.

Name:	zeus_DefinedContributionPlanVestingPeriod
Namespace Prefix:	zeus_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
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Data Type:	na
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Name:	us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis=zeus_CTILocation401KRetirementPlanMember
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Data Type:	na
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Name:	us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis=zeus_SupplementalExecutiveRetirementPlanSerpMember
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Note 16 - Retirement Plans (Details Textual) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Contribution Plan, Administrative Expenses	$ 2.2	$ 2.0	$ 2.2
Multiemployer Plan [Member] \| Minimum [Member]
Defined Benefit Plan, Funded Percentage	80.00%
Non-union Flat Rolled Segments’ 401K Retirement Plan [Member]
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay	6.00%
Defined Contribution Plan, Employer Matching Contribution, Percent of Match	50.00%
Union Flat Rolled Segments' 401K Retirement Plan [Member]
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay	6.00%
Defined Contribution Plan, Employer Matching Contribution, Percent of Match	50.00%
CTI Location 401K Retirement Plan [Member]
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay	6.00%
Defined Contribution Plan, Employer Matching Contribution, Percent of Match	50.00%
Supplemental Executive Retirement Plan (SERP) [Member]
Defined Contribution Plan, Compensation Percentage Multiplier	13.00%
Defined Contribution Plan Vesting Period	5 years