Note 14 - Capital Stock (Notes)	12 Months Ended
Dec. 31, 2017
Equity [Abstract]
Stockholders' Equity Note Disclosure [Text Block]	Capital Stock 2017 Activity On June 29, 2016, Radian Group’s board of directors authorized a share repurchase program to spend up to $125 million to repurchase Radian Group common stock. In order to implement the program, Radian adopted a trading plan under Rule 10b5-1 of the Exchange Act during the third quarter of 2016. During the second quarter of 2017, 380 shares were purchased at an average price of $15.59 per share, which represented the only purchases made under the plan. This share repurchase program expired on June 30, 2017. On August 9, 2017, Radian Group’s board of directors renewed its share repurchase program and authorized the Company to spend up to $50 million to repurchase Radian Group common stock in the open market or in privately negotiated transactions, based on market and business conditions, stock price and other factors. Radian has established a trading plan under Rule 10b5-1 of the Exchange Act to implement the program. As of December 31, 2017, no shares had been purchased and therefore the full purchase authority of up to $50 million remained available under this program, which expires on July 31, 2018. 2016 Activity In the first quarter of 2016, we announced and completed a share repurchase program. Pursuant to this program, we purchased an aggregate of 9.4 million shares of Radian Group common stock for $100.2 million, at a weighted-average price per share of $10.62, including commissions. No further purchase authority remains under this share repurchase program. As partial consideration for our March 2016 privately negotiated purchases of a portion of our Convertible Senior Notes due 2017 and 2019, we issued to the sellers 17.0 million shares of Radian Group common stock. In addition, in connection with our termination of the corresponding portion of the related capped call transactions, we received consideration of 0.2 million shares of Radian Group common stock. See Note 12 for additional information regarding these transactions. All shares of Radian Group common stock that we received from the above transactions were retired, resulting in a decrease in shares issued and outstanding and a corresponding increase in unissued shares. 2015 Activity As partial consideration for our June 2015 privately negotiated purchases of a portion of our Convertible Senior Notes due 2017, we issued to the sellers 28.4 million shares of Radian Group common stock. In addition, in partial consideration for our termination of the corresponding portion of the related capped call transactions, we received 2.3 million shares of Radian Group common stock. See Note 12 for additional information regarding these transactions. On June 18, 2015, we authorized an accelerated share repurchase program to repurchase an aggregate of $202 million of Radian Group common stock. Under the accelerated share repurchase program, the total number of shares ultimately delivered to Radian Group was based on the average of the daily volume-weighted-average price of Radian Group common stock during the term of the transaction, less a negotiated discount and subject to certain other adjustments pursuant to the terms and conditions of the program. During the three-month period ended June 30, 2015, 9.2 million shares were repurchased under this program. The counterparty delivered to Radian Group 1.8 million additional shares of Radian Group common stock at final settlement of the accelerated share repurchase program in August 2015, based on the calculated price of $18.32 during the term of the transaction. The shares of Radian Group common stock received pursuant to the accelerated share repurchase and the termination of the capped call transactions were retired, resulting in a decrease in shares issued and outstanding and a corresponding increase in unissued shares. All share repurchases pursuant to the accelerated share repurchase program were funded in the second quarter of 2015 from the proceeds of the Senior Notes due 2020. Other Purchases We may purchase shares on the open market to settle stock options exercised by employees and purchases under our Employee Stock Purchase Plan. Through December 31, 2017, from time to time we also purchased shares on the open market to fund certain 401(k) matches. In addition, upon the vesting of certain restricted stock awards under our equity compensation plans, we may withhold from such vested awards shares of our common stock to satisfy the tax liability of the award recipients.

Capital Stock

2017 Activity

On June 29, 2016, Radian Group’s board of directors authorized a share repurchase program to spend up to $125 million to repurchase Radian Group common stock. In order to implement the program, Radian adopted a trading plan under Rule 10b5-1 of the Exchange Act during the third quarter of 2016. During the second quarter of 2017, 380 shares were purchased at an average price of $15.59 per share, which represented the only purchases made under the plan. This share repurchase program expired on June 30, 2017.

On August 9, 2017, Radian Group’s board of directors renewed its share repurchase program and authorized the Company to spend up to $50 million to repurchase Radian Group common stock in the open market or in privately negotiated transactions, based on market and business conditions, stock price and other factors. Radian has established a trading plan under Rule 10b5-1 of the Exchange Act to implement the program. As of December 31, 2017, no shares had been purchased and therefore the full purchase authority of up to $50 million remained available under this program, which expires on July 31, 2018.

2016 Activity

In the first quarter of 2016, we announced and completed a share repurchase program. Pursuant to this program, we purchased an aggregate of 9.4 million shares of Radian Group common stock for $100.2 million, at a weighted-average price per share of $10.62, including commissions. No further purchase authority remains under this share repurchase program.

As partial consideration for our March 2016 privately negotiated purchases of a portion of our Convertible Senior Notes due 2017 and 2019, we issued to the sellers 17.0 million shares of Radian Group common stock. In addition, in connection with our termination of the corresponding portion of the related capped call transactions, we received consideration of 0.2 million shares of Radian Group common stock. See Note 12 for additional information regarding these transactions.

All shares of Radian Group common stock that we received from the above transactions were retired, resulting in a decrease in shares issued and outstanding and a corresponding increase in unissued shares.

2015 Activity

As partial consideration for our June 2015 privately negotiated purchases of a portion of our Convertible Senior Notes due 2017, we issued to the sellers 28.4 million shares of Radian Group common stock. In addition, in partial consideration for our termination of the corresponding portion of the related capped call transactions, we received 2.3 million shares of Radian Group common stock. See Note 12 for additional information regarding these transactions.

On June 18, 2015, we authorized an accelerated share repurchase program to repurchase an aggregate of $202 million of Radian Group common stock. Under the accelerated share repurchase program, the total number of shares ultimately delivered to Radian Group was based on the average of the daily volume-weighted-average price of Radian Group common stock during the term of the transaction, less a negotiated discount and subject to certain other adjustments pursuant to the terms and conditions of the program. During the three-month period ended June 30, 2015, 9.2 million shares were repurchased under this program. The counterparty delivered to Radian Group 1.8 million additional shares of Radian Group common stock at final settlement of the accelerated share repurchase program in August 2015, based on the calculated price of $18.32 during the term of the transaction. The shares of Radian Group common stock received pursuant to the accelerated share repurchase and the termination of the capped call transactions were retired, resulting in a decrease in shares issued and outstanding and a corresponding increase in unissued shares. All share repurchases pursuant to the accelerated share repurchase program were funded in the second quarter of 2015 from the proceeds of the Senior Notes due 2020.

Other Purchases

We may purchase shares on the open market to settle stock options exercised by employees and purchases under our Employee Stock Purchase Plan. Through December 31, 2017, from time to time we also purchased shares on the open market to fund certain 401(k) matches. In addition, upon the vesting of certain restricted stock awards under our equity compensation plans, we may withhold from such vested awards shares of our common stock to satisfy the tax liability of the award recipients.