1. NATURE OF BUSINESS AND BASIS OF PRESENTATION (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Commercial Insurance	$ 99,885us-gaap_InsuranceCommissionsAndFees	$ 98,881us-gaap_InsuranceCommissionsAndFees
Medicare	37,036rdnt_HealthCareOrganizationMedicare	36,202rdnt_HealthCareOrganizationMedicare
Medicaid	5,470	5,774
Workers Compensation/Personal Injury	7,400rdnt_WorkersCompensationpersonalInjury	9,635rdnt_WorkersCompensationpersonalInjury
Other	15,239	8,271
Service fee revenue, net of contractual allowances and discounts	165,030	158,763
Provision for bad debts	(7,475)	(6,893)
Net service fee revenue	157,555	151,870
Revenue under capitation arrangements	23,712	17,006
Total net revenue	$ 181,267us-gaap_SalesRevenueNet	$ 168,876us-gaap_SalesRevenueNet

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Workers Compensation/Personal Injury

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Amount of revenue recognized based on fees charged on a per capita basis.

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 954

-SubTopic 605

-Section 45

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Amount of revenue recognized that is not otherwise disclosed.

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-Topic 225

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Amount of revenue recognized for providing services to patients, net of provisions for contractual allowances and discounts.

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Amount of patient service revenue, net of contractual allowances and discounts, less the related provision for bad debts.

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Amount of the provision for bad debts related to patient service revenue.

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Amount of insurance premium revenue recognized.

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Income from agency and brokerage operations (includes sales of annuities and supplemental contracts); service charges, commissions, and fees from the sale of insurance and related services; and management fees from separate accounts, deferred annuities, and universal life products.

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Total revenue from sale of goods and services rendered during the reporting period, in the normal course of business, reduced by sales returns and allowances, and sales discounts.

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