Commitments And Contingencies [Line Items]

No definition available.

Name:	rdi_CommitmentsAndContingenciesLineItems
Namespace Prefix:	rdi_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Common Stock, Additional Voting Stock Ownership Percent That May Awarded

+ References

No definition available.

+ Details

Name:	rdi_CommonStockAdditionalVotingStockOwnershipPercentThatMayAwarded
Namespace Prefix:	rdi_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Common Stock, Shares Held in Estate

+ References

No definition available.

+ Details

Name:	rdi_CommonStockSharesHeldInEstate
Namespace Prefix:	rdi_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Common Stock, Voting Stock Ownership Percent

+ References

No definition available.

+ Details

Name:	rdi_CommonStockVotingStockOwnershipPercent
Namespace Prefix:	rdi_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Common Stock, Voting Stock Ownership Percent Outstanding

+ References

No definition available.

+ Details

Name:	rdi_CommonStockVotingStockOwnershipPercentOutstanding
Namespace Prefix:	rdi_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Income Tax Examination, Income Tax Obligation

+ References

No definition available.

+ Details

Name:	rdi_IncomeTaxExaminationIncomeTaxObligation
Namespace Prefix:	rdi_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Insurance, Coverage Limit

+ References

No definition available.

+ Details

Name:	rdi_InsuranceCoverageLimit
Namespace Prefix:	rdi_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Litigation Settlement Interest, Percent

+ References

No definition available.

+ Details

Name:	rdi_LitigationSettlementInterestPercent
Namespace Prefix:	rdi_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount awarded from other party in judgment or settlement of litigation.

+ References

No definition available.

+ Details

Name:	us-gaap_LitigationSettlementAmountAwardedFromOtherParty
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of litigation expense, including but not limited to legal, forensic, accounting, and investigative fees.

+ References

No definition available.

+ Details

Name:	us-gaap_LitigationSettlementExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Reflects the estimated amount of loss from the specified contingency as of the balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=82911808&loc=d3e14435-108349

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 9
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=82911808&loc=d3e14557-108349

+ Details

Name:	us-gaap_LossContingencyEstimateOfPossibleLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Price of a single share of a number of saleable stocks of a company.

+ References

No definition available.

+ Details

Name:	us-gaap_SharePrice
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	us-gaap_LitigationCaseAxis=rdi_TaxAuditLitigationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LitigationCaseAxis=rdi_JamesJ.CotterJr.LitigationMattersMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LitigationCaseAxis=rdi_StompArbitrationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=rdi_CotterTrustMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=rdi_EllenCotterAndMargaretCotterMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementClassOfStockAxis=us-gaap_CommonClassBMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=rdi_CotterEstateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=rdi_CotterVotingTrustMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Commitments And Contingencies (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended	2 Months Ended	12 Months Ended
	Apr. 30, 2016	Dec. 31, 2017	Dec. 31, 2017	Feb. 08, 2017	Aug. 03, 2016	May 31, 2016
Tax Audit/Litigation [Member]
Commitments And Contingencies [Line Items]
Income tax obligation		$ 2.8	$ 2.8
Cotter, Jr. Related Litigation Matters [Member]
Commitments And Contingencies [Line Items]
Amount of damages claimed by plaintiff		1.2	1.2
Litigation expense		$ 1.7	4.0
Coverage limit			$ 10.0
The STOMP Arbitration [Member]
Commitments And Contingencies [Line Items]
Settlement awarded	$ 2.3
Litigation interest percent	4.00%
Cotter Trust [Member] \| Cotter, Jr. Related Litigation Matters [Member]
Commitments And Contingencies [Line Items]
Share price				$ 18.50
Ellen Cotter And Margaret Cotter [Member] \| Cotter, Jr. Related Litigation Matters [Member]
Commitments And Contingencies [Line Items]
Outstanding voting stock percent			71.90%
Class B [Member] \| Cotter, Jr. Related Litigation Matters [Member]
Commitments And Contingencies [Line Items]
Shares held by estate					100,000
Class B [Member] \| Cotter Estate [Member] \| Cotter, Jr. Related Litigation Matters [Member]
Commitments And Contingencies [Line Items]
Shares held by estate		427,808	427,808			327,808
Class B [Member] \| Cotter Estate [Member] \| Cotter, Jr. Related Litigation Matters [Member] \| Maximum [Member]
Commitments And Contingencies [Line Items]
Additional voting stock that may be awarded			25.50%
Class B [Member] \| Cotter Trust [Member] \| Cotter, Jr. Related Litigation Matters [Member]
Commitments And Contingencies [Line Items]
Shares held by estate		696,080	696,080			696,080
Voting stock percent			41.40%
Class B [Member] \| Cotter Voting Trust [Member] \| Cotter, Jr. Related Litigation Matters [Member]
Commitments And Contingencies [Line Items]
Voting stock percent			66.90%