XML 33 R27.htm IDEA: XBRL DOCUMENT
v3.19.3.a.u2

Summary of Significant Accounting Policies (Tables) | 12 Months Ended
--- | ---
Dec. 31, 2019
Summary of Significant Accounting Policies |
Components of self-insurance reserves | ​
​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | December 31,
​ |  | 2019 |  | 2018
Self-insurance reserves (undiscounted) | ​ | $ | 168,397 | ​ | $ | 157,538
Self-insurance reserves (discounted) | ​ |  | 156,585 | ​ |  | 146,718

X
- Definition Table containing amount of undiscounted and discounted self-insurance reserves the Company had at the balance sheet date. + References No definition available. + Details
Name: | orly_SelfInsuranceReservesTableTextBlock
Namespace Prefix: | orly_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_PolicyTextBlockAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration