Commitments (Commitments) (Narrative) (Details) (USD $) In Millions, unless otherwise specified	0 Months Ended
Jan. 14, 2011 D	Dec. 31, 2012
Commitments
Construction commitments		$ 89.3
Letters of credit		$ 57.3
Debt instrument minimum number of days callable	30
Debt instrument maximum number of days callable	60
Percentage principal amount of debt that can be redeemed by the Company	100.00%
Percentage principal amount of debt redeemable upon change in control	101.00%

Commitments which may be required to perform construction-type contracts as of the balance sheet date.

No definition available.

Name:	orly_ConstructionCommitments
Namespace Prefix:	orly_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

As described in the Indenture governing the notes, the fewest number of days notice the Company must give to call the notes.

No definition available.

Name:	orly_DebtInstrumentCallFeatureEarliestNumberOfDaysCallable
Namespace Prefix:	orly_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

As described in the Indenture governing the notes, the maximum number of days notice the Company must give to call the notes.

No definition available.

Name:	orly_DebtInstrumentCallFeatureLatestNumberOfDaysCallable
Namespace Prefix:	orly_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

The percentage of the principal amount of the debt instrument that can be redeemed upon a change in control triggering event.

No definition available.

Name:	orly_PercentOfDebtInstrumentPrincipalAmountRedeemableUponChangeInControl
Namespace Prefix:	orly_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

The percentage of the principal amount of the debt instrument that can be redeemed at the option of the Company.

No definition available.

Name:	orly_PercentOfDebtInstrumentPrincipalAmountRedeemed
Namespace Prefix:	orly_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

No definition available.

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

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