Debt Instrument, Extension Period

No definition available.

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Balance Type:	na
Period Type:	duration

- Definition

Debt Instrument, Leverage Ratio

+ References

No definition available.

+ Details

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Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Debt Instrument, Periodic Payment, Percent

+ References

No definition available.

+ Details

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Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt Instrument, Periodic Payment Terms, Amortization Increase

+ References

No definition available.

+ Details

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Namespace Prefix:	rdnt_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Line of Credit Facility, Increase Borrowing Capacity

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The amount of amortization of deferred charges applied against earnings during the period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.3)
-URI http://asc.fasb.org/extlink&oid=123367319&loc=SL114868664-224227

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

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

+ References

No definition available.

+ Details

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

- Definition

Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 6
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-Section 45
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-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

Name:	us-gaap_DebtInstrumentInterestRateEffectivePercentage
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Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- 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

Amount of the required periodic payments applied to principal.

+ References

+ Details

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

- Definition

Amount of debt discount to be amortized within one year or within the normal operating cycle, if longer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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+ Details

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

- Definition

Amount, before accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
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-Paragraph 3
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+ Details

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

- Definition

Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
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-Paragraph 1
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Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
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-Name Accounting Standards Codification
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-Section 50
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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity.

+ References

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+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

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

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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+ Details

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

- Definition

The fee, expressed as a percentage of the line of credit facility, for the line of credit facility regardless of whether the facility has been used.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
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

+ Details

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

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

+ Details

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

- Definition

The fee, expressed as a percentage of the line of credit facility, for available but unused credit capacity under the credit facility.

+ References

No definition available.

+ Details

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Period Type:	duration

- Details

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Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=rdnt_FirstLienCreditAgreementSeventhAmendmentMember
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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:	us-gaap_LineOfCreditFacilityAxis=rdnt_BarclaysMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_LetterOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LineOfCreditFacilityAxis=rdnt_SunTrustMember
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Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=rdnt_TermLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_LineOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=rdnt_FirstLienCreditAgreementMember
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Data Type:	na
Balance Type:
Period Type:

- Details

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- Details

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- Details

Name:	us-gaap_DebtInstrumentAxis=rdnt_FirstLienTermLoanMember
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Balance Type:
Period Type:

- Details

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Balance Type:
Period Type:

- Details

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Data Type:	na
Balance Type:
Period Type:

- Details

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- Details

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CREDIT FACILITY AND NOTES PAYABLE (Details Narrative)					3 Months Ended	6 Months Ended		12 Months Ended
CREDIT FACILITY AND NOTES PAYABLE (Details Narrative)	Apr. 23, 2021 USD ($)	Apr. 18, 2019 USD ($)	Dec. 31, 2018 USD ($)	Aug. 31, 2018	Mar. 31, 2021	Jun. 30, 2021 USD ($)	Jun. 30, 2020 USD ($)	Dec. 31, 2020 USD ($)	Aug. 28, 2020 USD ($)
Debt Instrument [Line Items]
Total credit facilities outstanding						$ 0		$ 0
Deferred financing costs, net of accumulated amortization						2,400,000		1,800,000
Debt restructuring and extinguishment expenses	$ 1,500,000					(1,496,000)	$ 0
Term loan
Debt Instrument [Line Items]
Total credit facilities outstanding	725,000,000.0
First Lien Credit Agreement Seventh Amendment
Debt Instrument [Line Items]
Debt issuance costs	14,900,000
Debt discount	8,800,000
Deferred financing costs, net of accumulated amortization	4,500,000
Amortization of deferred issuance costs	$ 100,000
Revolving Credit Facility
Debt Instrument [Line Items]
Letters of credit outstanding						7,800,000
Deferred financing costs, net of accumulated amortization						$ 2,400,000
Effective interest rate						5.25%
Barclays \| Revolving Credit Facility
Debt Instrument [Line Items]
Line of credit facility, remaining borrowing capacity						$ 187,200,000
Barclays \| Revolving Credit Facility \| Letter of Credit
Debt Instrument [Line Items]
Commitment fee percentage						0.125%
Unused capacity, commitment fee percentage						0.50%
SunTrust \| Term Loans
Debt Instrument [Line Items]
Periodic payment, principal			$ 800,000
Periodic payment, percent			5.00%
Periodic payment amortization increase			$ 400,000
SunTrust \| Revolving Credit Facility \| Line of Credit
Debt Instrument [Line Items]
Maximum borrowing capacity						$ 30,000,000.0
First Lien Credit Agreement \| Barclays \| Revolving Credit Facility \| Line of Credit
Debt Instrument [Line Items]
Total credit facilities outstanding						0		$ 0
First Lien Credit Agreement \| SunTrust \| Revolving Credit Facility \| Line of Credit
Debt Instrument [Line Items]
Total credit facilities outstanding						0
First Lien Credit Agreement Eighth Amendment \| Barclays \| Revolving Credit Facility \| Line of Credit
Debt Instrument [Line Items]
Maximum borrowing capacity									$ 195,000,000.0
Line of credit facility, increase borrowing capacity									$ 57,500,000
First Lien Credit Agreement, Sixth Amendment \| Term loan
Debt Instrument [Line Items]
Total credit facilities outstanding		$ 100,000,000.0
First Lien Credit Agreement, Sixth Amendment \| Revolving Credit Facility \| Line of Credit
Debt Instrument [Line Items]
Line of credit facility, increase borrowing capacity		$ 20,000,000.0
Extension period		2 years
Leverage ratio					3.00
First Lien Term Loan \| Barclays \| Term Loans
Debt Instrument [Line Items]
Periodic payment, principal						$ 1,800,000
Pricing Level III \| SunTrust Term Loan \| Revolving Credit Facility
Debt Instrument [Line Items]
Commitment fee percentage				2.00%
Unused capacity, commitment fee percentage				0.35%
Eurodollar Rate Spread \| First Lien Credit Agreement, Sixth Amendment \| Revolving Credit Facility \| Line of Credit
Debt Instrument [Line Items]
Effective interest rate						0.75%
Basis spread on variable rate					3.00%			3.25%
Eurodollar Rate Spread \| Leverage Ratio Three \| First Lien Credit Agreement, Sixth Amendment \| Revolving Credit Facility \| Line of Credit
Debt Instrument [Line Items]
Basis spread on variable rate						3.00%
Eurodollar Rate Spread \| Pricing Level III \| SunTrust Term Loan \| Revolving Credit Facility
Debt Instrument [Line Items]
Basis spread on variable rate				2.00%		0.20%
Alternate Base Rate Spread \| First Lien Credit Agreement, Sixth Amendment \| Revolving Credit Facility \| Line of Credit
Debt Instrument [Line Items]
Effective interest rate						3.25%
Alternate Base Rate Spread \| Leverage Ratio Three \| First Lien Credit Agreement, Sixth Amendment \| Revolving Credit Facility \| Line of Credit
Debt Instrument [Line Items]
Basis spread on variable rate						2.00%
Alternate Base Rate Spread \| Pricing Level III \| SunTrust Term Loan \| Revolving Credit Facility
Debt Instrument [Line Items]
Basis spread on variable rate				1.00%