Note 1 - Description of Business and Recent Developments Level 1 (Notes)	12 Months Ended
Dec. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Business Description and Basis of Presentation [Text Block]	Description of Business and Recent Developments We are a diversified mortgage and real estate services business, providing both credit-related insurance coverage and other credit risk management solutions, as well as a broad array of mortgage and real estate services. We have two reportable business segments—Mortgage Insurance and Services. On April 1, 2015, Radian Guaranty completed the sale of its former financial guaranty subsidiary, Radian Asset Assurance, to Assured, pursuant to the Radian Asset Assurance Stock Purchase Agreement. The operating results of Radian Asset Assurance were classified as discontinued operations. See Note 18 for additional information related to discontinued operations. Mortgage Insurance Our Mortgage Insurance segment provides credit-related insurance coverage, principally through private mortgage insurance, as well as other credit risk management solutions, to mortgage lending institutions nationwide. Private mortgage insurance plays an important role in the U.S. housing finance system because it promotes affordable home ownership and helps protect mortgage lenders, investors or other beneficiaries by mitigating default-related losses on residential mortgage loans. Generally, these loans are made to home buyers who make down payments of less than 20% of the purchase price for their home or, in the case of refinancings, have less than 20% equity in their homes. Private mortgage insurance also facilitates the sale of these low down payment loans in the secondary mortgage market, most of which are sold to the GSEs. Our Mortgage Insurance segment currently offers primary mortgage insurance coverage on residential first-lien mortgage loans. Our total direct primary mortgage insurance RIF was $51.3 billion as of December 31, 2017. We provide our mortgage insurance products and services mainly through our wholly-owned subsidiary, Radian Guaranty. The GSEs and state insurance regulators impose various capital and financial requirements on our insurance subsidiaries. These include Risk-to-capital, other risk-based capital measures and surplus requirements, as well as the PMIERs financial requirements discussed below. Failure to comply with these capital and financial requirements may limit the amount of insurance that our insurance subsidiaries may write or prohibit our insurance subsidiaries from writing insurance altogether. The GSEs and state insurance regulators also possess significant discretion with respect to our insurance subsidiaries and all aspects of their business. See Note 19 for additional regulatory information. PMIERs. In order to be eligible to insure loans purchased by the GSEs, mortgage insurers such as Radian Guaranty must meet the GSEs’ eligibility requirements, or PMIERs. At December 31, 2017, Radian Guaranty is an approved mortgage insurer under the PMIERs and is in compliance with the PMIERs financial requirements. The PMIERs are comprehensive, covering virtually all aspects of the business and operations of a private mortgage insurer, including internal risk management and quality controls, the relationship between the GSEs and the approved insurer, as well as the approved insurer’s financial condition. In addition, private mortgage insurers are required under the PMIERs to obtain the prior consent of the GSEs before taking certain actions, which may include paying dividends, entering into various intercompany agreements, and commuting or reinsuring risk, among others. If Radian Guaranty is unable to satisfy the requirements set forth in the PMIERs, the GSEs could restrict it from conducting certain types of business with them or take actions that may include not purchasing loans insured by Radian Guaranty. The PMIERs financial requirements require that a mortgage insurer’s Available Assets meet or exceed its Minimum Required Assets. The GSEs may amend the PMIERs at any time, and they have broad discretion to interpret the requirements, which could impact the calculation of Radian Guaranty’s Available Assets and/or Minimum Required Assets, and the PMIERs specifically provide that the factors that are applied to calculate and determine a mortgage insurer’s Minimum Required Assets may be updated every two years following a minimum of 180 days’ notice, or more frequently, as determined by the GSEs, to reflect changes in macroeconomic conditions or loan performance. On December 18, 2017, Radian Guaranty received, on a confidential basis, a summary of proposed changes to the PMIERs. Although it is reasonably likely that updates to the PMIERs could, among other things, result in a material increase to Radian Guaranty’s capital requirements under the PMIERs financial requirements, Radian expects to be able to fully comply with the proposed PMIERs as of the expected effective date in late 2018. From time to time, we enter into reinsurance transactions as part of our strategy to manage our capital position and risk profile, which includes managing Radian Guaranty’s position under the PMIERs financial requirements. The credit that we receive under the PMIERs financial requirements for these transactions is subject to the periodic review of the GSEs. Services Our Services business is a fee-for-service business that offers a broad array of services to market participants across the mortgage and real estate value chain. These comprise mortgage services and real estate services that provide mortgage lenders, financial institutions, mortgage and real estate investors and government entities, among others, with information and other resources and services that are used to originate, evaluate, acquire, securitize, service and monitor residential real estate and loans secured by residential real estate. Our mortgage services offerings include transaction management services such as loan review, RMBS securitization and distressed asset reviews, servicer and loan surveillance and underwriting. Our real estate services include: REO asset management; review and valuation services related to single family rental properties; real estate valuation services; real estate brokerage services; and title and settlement services that include title search, settlement and closing services. Discontinued Operations On April 1, 2015, Radian Guaranty completed the sale of 100% of the issued and outstanding shares of Radian Asset Assurance, its former financial guaranty subsidiary, for a purchase price of approximately $810 million, pursuant to the Radian Asset Assurance Stock Purchase Agreement. The divestiture was intended to better position Radian Guaranty to comply with the PMIERs and to support Radian’s strategic focus on the mortgage and real estate industries. After closing costs and other adjustments, Radian Guaranty received net proceeds of $789 million. For additional information related to discontinued operations, see Note 18. 2017 Developments Capital and Liquidity Actions. During 2017, we completed a series of capital and liquidity actions, including: (i) extending the weighted average maturity of our Senior Notes by purchasing a portion of our Senior Notes due 2019, 2020 and 2021 through tender offers and issuing our Senior Notes due 2024; (ii) eliminating our Convertible Senior Notes due 2017 and 2019; (iii) entering into a $225 million unsecured revolving credit facility; and (iv) renewing our share repurchase program. These transactions strengthened our capital and liquidity position and improved our financial flexibility, including by improving our debt maturity profile. See Notes 12 and 14 for additional information. Restructuring and Other Exit Costs. Based on our strategic assessment of the Services business, on September 5, 2017, the Company committed to a plan to restructure the Services business and incurred pretax restructuring charges of $17.3 million in 2017, including $6.8 million in cash payments. Additional pretax restructuring charges of approximately $3.8 million, including approximately $3.0 million in cash, are expected to be recognized within the next 12 months. The total restructuring charges of approximately $21.1 million are expected to consist of: (i) asset impairment charges (including the loss recognized on the sale of our EuroRisk business) of approximately $11.3 million; (ii) employee severance and benefit costs of approximately $7.1 million; (iii) facility and lease termination costs of approximately $1.8 million; and (iv) contract termination and other restructuring costs of approximately $0.9 million. See Note 7 for additional information, including the events that led to the restructuring decision. Impairment of Goodwill and Other Intangible Assets. During the second quarter of 2017, we recorded a goodwill impairment charge and an impairment charge for other intangible assets. See Note 7 for additional information. Reinsurance. During 2017, we entered into the 2018 Single Premium QSR Transaction with a panel of reinsurers and we amended the terms of the 2016 Single Premium QSR Transaction to increase the ceded risk on performing loans from 35% to 65% for the 2015 through 2017 vintages. See Note 8 for additional information about our reinsurance transactions.

Description of Business and Recent Developments

We are a diversified mortgage and real estate services business, providing both credit-related insurance coverage and other credit risk management solutions, as well as a broad array of mortgage and real estate services. We have two reportable business segments—Mortgage Insurance and Services. On April 1, 2015, Radian Guaranty completed the sale of its former financial guaranty subsidiary, Radian Asset Assurance, to Assured, pursuant to the Radian Asset Assurance Stock Purchase Agreement. The operating results of Radian Asset Assurance were classified as discontinued operations. See Note 18 for additional information related to discontinued operations.

Mortgage Insurance

Our Mortgage Insurance segment provides credit-related insurance coverage, principally through private mortgage insurance, as well as other credit risk management solutions, to mortgage lending institutions nationwide. Private mortgage insurance plays an important role in the U.S. housing finance system because it promotes affordable home ownership and helps protect mortgage lenders, investors or other beneficiaries by mitigating default-related losses on residential mortgage loans. Generally, these loans are made to home buyers who make down payments of less than 20% of the purchase price for their home or, in the case of refinancings, have less than 20% equity in their homes. Private mortgage insurance also facilitates the sale of these low down payment loans in the secondary mortgage market, most of which are sold to the GSEs.

Our Mortgage Insurance segment currently offers primary mortgage insurance coverage on residential first-lien mortgage loans. Our total direct primary mortgage insurance RIF was $51.3 billion as of December 31, 2017. We provide our mortgage insurance products and services mainly through our wholly-owned subsidiary, Radian Guaranty.

The GSEs and state insurance regulators impose various capital and financial requirements on our insurance subsidiaries. These include Risk-to-capital, other risk-based capital measures and surplus requirements, as well as the PMIERs financial requirements discussed below. Failure to comply with these capital and financial requirements may limit the amount of insurance that our insurance subsidiaries may write or prohibit our insurance subsidiaries from writing insurance altogether. The GSEs and state insurance regulators also possess significant discretion with respect to our insurance subsidiaries and all aspects of their business. See Note 19 for additional regulatory information.

PMIERs. In order to be eligible to insure loans purchased by the GSEs, mortgage insurers such as Radian Guaranty must meet the GSEs’ eligibility requirements, or PMIERs. At December 31, 2017, Radian Guaranty is an approved mortgage insurer under the PMIERs and is in compliance with the PMIERs financial requirements.

The PMIERs are comprehensive, covering virtually all aspects of the business and operations of a private mortgage insurer, including internal risk management and quality controls, the relationship between the GSEs and the approved insurer, as well as the approved insurer’s financial condition. In addition, private mortgage insurers are required under the PMIERs to obtain the prior consent of the GSEs before taking certain actions, which may include paying dividends, entering into various intercompany agreements, and commuting or reinsuring risk, among others. If Radian Guaranty is unable to satisfy the requirements set forth in the PMIERs, the GSEs could restrict it from conducting certain types of business with them or take actions that may include not purchasing loans insured by Radian Guaranty.

The PMIERs financial requirements require that a mortgage insurer’s Available Assets meet or exceed its Minimum Required Assets. The GSEs may amend the PMIERs at any time, and they have broad discretion to interpret the requirements, which could impact the calculation of Radian Guaranty’s Available Assets and/or Minimum Required Assets, and the PMIERs specifically provide that the factors that are applied to calculate and determine a mortgage insurer’s Minimum Required Assets may be updated every two years following a minimum of 180 days’ notice, or more frequently, as determined by the GSEs, to reflect changes in macroeconomic conditions or loan performance. On December 18, 2017, Radian Guaranty received, on a confidential basis, a summary of proposed changes to the PMIERs. Although it is reasonably likely that updates to the PMIERs could, among other things, result in a material increase to Radian Guaranty’s capital requirements under the PMIERs financial requirements, Radian expects to be able to fully comply with the proposed PMIERs as of the expected effective date in late 2018.

From time to time, we enter into reinsurance transactions as part of our strategy to manage our capital position and risk profile, which includes managing Radian Guaranty’s position under the PMIERs financial requirements. The credit that we receive under the PMIERs financial requirements for these transactions is subject to the periodic review of the GSEs.

Services

Our Services business is a fee-for-service business that offers a broad array of services to market participants across the mortgage and real estate value chain. These comprise mortgage services and real estate services that provide mortgage lenders, financial institutions, mortgage and real estate investors and government entities, among others, with information and other resources and services that are used to originate, evaluate, acquire, securitize, service and monitor residential real estate and loans secured by residential real estate.

Our mortgage services offerings include transaction management services such as loan review, RMBS securitization and distressed asset reviews, servicer and loan surveillance and underwriting. Our real estate services include: REO asset management; review and valuation services related to single family rental properties; real estate valuation services; real estate brokerage services; and title and settlement services that include title search, settlement and closing services.

Discontinued Operations

On April 1, 2015, Radian Guaranty completed the sale of 100% of the issued and outstanding shares of Radian Asset Assurance, its former financial guaranty subsidiary, for a purchase price of approximately $810 million, pursuant to the Radian Asset Assurance Stock Purchase Agreement. The divestiture was intended to better position Radian Guaranty to comply with the PMIERs and to support Radian’s strategic focus on the mortgage and real estate industries. After closing costs and other adjustments, Radian Guaranty received net proceeds of $789 million. For additional information related to discontinued operations, see Note 18.

2017 Developments

Capital and Liquidity Actions. During 2017, we completed a series of capital and liquidity actions, including: (i) extending the weighted average maturity of our Senior Notes by purchasing a portion of our Senior Notes due 2019, 2020 and 2021 through tender offers and issuing our Senior Notes due 2024; (ii) eliminating our Convertible Senior Notes due 2017 and 2019; (iii) entering into a $225 million unsecured revolving credit facility; and (iv) renewing our share repurchase program. These transactions strengthened our capital and liquidity position and improved our financial flexibility, including by improving our debt maturity profile. See Notes 12 and 14 for additional information.

Restructuring and Other Exit Costs. Based on our strategic assessment of the Services business, on September 5, 2017, the Company committed to a plan to restructure the Services business and incurred pretax restructuring charges of $17.3 million in 2017, including $6.8 million in cash payments. Additional pretax restructuring charges of approximately $3.8 million, including approximately $3.0 million in cash, are expected to be recognized within the next 12 months. The total restructuring charges of approximately $21.1 million are expected to consist of: (i) asset impairment charges (including the loss recognized on the sale of our EuroRisk business) of approximately $11.3 million; (ii) employee severance and benefit costs of approximately $7.1 million; (iii) facility and lease termination costs of approximately $1.8 million; and (iv) contract termination and other restructuring costs of approximately $0.9 million. See Note 7 for additional information, including the events that led to the restructuring decision.

Impairment of Goodwill and Other Intangible Assets. During the second quarter of 2017, we recorded a goodwill impairment charge and an impairment charge for other intangible assets. See Note 7 for additional information.

Reinsurance. During 2017, we entered into the 2018 Single Premium QSR Transaction with a panel of reinsurers and we amended the terms of the 2016 Single Premium QSR Transaction to increase the ceded risk on performing loans from 35% to 65% for the 2015 through 2017 vintages. See Note 8 for additional information about our reinsurance transactions.