The percent of face value, at which the debt instrument was offered to the public.

No definition available.

Name:	orly_DebtInstrumentPricing
Namespace Prefix:	orly_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The redemption price of the debt that is being redeemed.

+ References

No definition available.

+ Details

Name:	orly_DebtInstrumentRedemptionPrice
Namespace Prefix:	orly_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The number of days in a year used to calculate interest.

+ References

No definition available.

+ Details

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

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=119993939&loc=d3e28551-108399

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

+ Details

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

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

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

- 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

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

- Definition

Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 50
-Section 40
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=117329964&loc=d3e12355-112629

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 50
-Section 40
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=117329964&loc=d3e12317-112629

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 (b)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3602-108585

+ Details

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

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_SeniorNotesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=orly_SeniorNotesDue2030At4200Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=orly_SeniorNotesDue2031At1750Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=orly_SeniorNotesDue2021At4875Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=orly_SeniorNotesDue2029At3900Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=orly_SeniorNotesDue2021At4625Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BalanceSheetLocationAxis=us-gaap_LongTermDebtMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Financing (Senior Notes) (Narrative) (Details) $ in Thousands				12 Months Ended
	Oct. 14, 2020 USD ($)	Sep. 23, 2020 USD ($) D	Mar. 27, 2020 USD ($) D	Dec. 31, 2020 USD ($) D	Dec. 31, 2019 USD ($)
Senior notes [Member]
Financing
Face amount of senior notes				$ 4,200,000
Number of days in annual interest calculation period \| D				360
Minimum [Member] \| Senior notes [Member]
Financing
Interest rate of senior notes				1.75%
Maximum [Member] \| Senior notes [Member]
Financing
Interest rate of senior notes				4.625%
4.200% Senior Notes due 2030 [Member]
Financing
Face amount of senior notes			$ 500,000
Interest rate of senior notes			4.20%
Percentage of face value of debt instrument			99.959%
Number of days in annual interest calculation period \| D			360
4.200% Senior Notes due 2030 [Member] \| Senior notes [Member]
Financing
Face amount of senior notes				$ 500,000	$ 0
Interest rate of senior notes				4.20%
1.750% Senior Notes due 2031 [Member]
Financing
Face amount of senior notes		$ 500,000
Interest rate of senior notes		1.75%
Percentage of face value of debt instrument		99.544%
Number of days in annual interest calculation period \| D		360
1.750% Senior Notes due 2031 [Member] \| Senior notes [Member]
Financing
Face amount of senior notes				$ 500,000	0
Interest rate of senior notes				1.75%
4.875% Senior Notes due 2021 [Member]
Financing
Face amount of senior notes	$ 500,000
Debt redemption price	500,000
Loss on debt extinguishment	$ (200)
4.875% Senior Notes due 2021 [Member] \| Senior notes [Member]
Financing
Face amount of senior notes				$ 0	$ 500,000
Interest rate of senior notes					4.875%
3.900% Senior Notes due 2029 [Member] \| Senior notes [Member]
Financing
Face amount of senior notes				$ 500,000	$ 500,000
Interest rate of senior notes				3.90%	3.90%
4.625% Senior Notes due 2021 [Member] \| Senior notes [Member]
Financing
Interest rate of senior notes				4.625%	4.625%
4.625% Senior Notes due 2021 [Member] \| Senior notes [Member] \| Long-term Debt [Member]
Financing
Face amount of senior notes				$ 300,000	$ 300,000