Consolidated Statements of Cash Flows (Parenthetical) $ in Millions	12 Months Ended
Dec. 31, 2018 USD ($)
Statement of Cash Flows [Abstract]
Special dividend declared in December 2017 and paid in January 2018	$ 269.2

Special dividend declared in December 2017 and paid in January 2018

No definition available.

Name:	ori_SpecialdividenddeclaredinDecember2017andpaidinJanuary2018
Namespace Prefix:	ori_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration