Legal Matters (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Legal Matters
Former CSK officer clawback	$ (2,798)	$ 0	$ 0	$ 0	$ (2,798)	$ 0	$ 0
Legacy CSK DOJ indemnity litigation reserve					$ 14,100

A reduction of selling, general and administrative expense for previously paid incentive-based compensation and stock sale profits as a result of a Securities and Exchange Commission clawback settlement.

No definition available.

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Namespace Prefix:	orly_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration