Percentage points added to the reference rate to compute the variable rate on the debt instrument.

No definition available.

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(2))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bbb)(2)
-URI http://asc.fasb.org/extlink&oid=99377789&loc=d3e19207-110258

+ Details

Name:	us-gaap_DebtInstrumentMaturityDate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	us-gaap_DebtInstrumentAxis=rdi_NationalAustraliaBankAustralianCorporateTermLoanAndRevolverTierOneMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=rdi_NationalAustraliaBankAustralianCorporateTermLoanAndRevolverTierTwoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=rdi_NationalAustraliaBankAustralianCorporateTermLoanAndRevolverTierThreeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LineOfCreditFacilityAxis=rdi_BankGuaranteeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LineOfCreditFacilityAxis=rdi_CoreFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Borrowings (Australian NAB Corporate Loan Facility) (Narrative) (Details) - AUD ($) $ in Millions			12 Months Ended
	Mar. 15, 2019	Dec. 17, 2018	Dec. 31, 2018
Australian NAB Corporate Loan Facility Tier 1 [Member]
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity			$ 66.5
Spread on variable interest rate		0.95%
Maturity date			Jun. 30, 2019
Australian NAB Corporate Loan Facility Tier 2 [Member]
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity			$ 5.0
Spread on variable interest rate		1.90%
Australian NAB Corporate Loan Facility Tier 3 [Member]
Debt Instrument [Line Items]
Maturity date			Dec. 31, 2023
Subsequent Event [Member] \| Australian NAB Corporate Loan Facility Tier 3 [Member]
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity	$ 120.0
Subsequent Event [Member] \| Australian NAB Corporate Loan Facility Tier 3 [Member] \| Bank Guarantee Facility [Member]
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity	$ 5.0
Spread on variable interest rate	1.85%
Subsequent Event [Member] \| Australian NAB Corporate Loan Facility Tier 3 [Member] \| Core Facility [Member]
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity	$ 40.0
Subsequent Event [Member] \| Australian NAB Corporate Loan Facility Tier 3 [Member] \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity	$ 80.0
Subsequent Event [Member] \| Minimum [Member] \| Australian NAB Corporate Loan Facility Tier 3 [Member]
Debt Instrument [Line Items]
Spread on variable interest rate	0.85%
Subsequent Event [Member] \| Maximum [Member] \| Australian NAB Corporate Loan Facility Tier 3 [Member]
Debt Instrument [Line Items]
Spread on variable interest rate	1.30%