Basis of Presentation (Narrative) (Details) $ in Millions	Sep. 30, 2020 USD ($)
Basis of Presentation
Equity method investment in VIEs, net	$ 13.2

The carrying amount of the reporting entity's equity method investment in a Variable Interest Entity included in the reporting entity's statement of financial position.

No definition available.

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