Legal Matters (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014
Loss Contingency [Abstract]
Legacy CSK DOJ indemnity litigation reserve	$ 11.6orly_IndemnityLitigationReserve

Aggregate carrying amount of reserve, as of the balance sheet date, for known or estimated legal fees pertaining to indemnity obligations.

No definition available.

Name:	orly_IndemnityLitigationReserve
Namespace Prefix:	orly_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration