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Share-Based Compensation and Other Benefit Programs - Additional Information (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2024 USD ($) Anniversary $ / shares shares	Dec. 31, 2023 USD ($) Anniversary $ / shares shares	Dec. 31, 2022 USD ($) Anniversary $ / shares shares	Feb. 28, 2025 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum percentage of base earnings qualifying for pre-tax contributions	100.00%
Matching contribution percentage	100.00%
Base earnings qualifying for parent company matching contribution, percent	6.00%
Matching funds expense	$ 8,000	$ 8,000	$ 10,000
Performance-Based
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average grant date fair value (in usd per share) \| $ / shares	$ 29.32
Performance-Based \| 2021 Award Year
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average grant date fair value (in usd per share) \| $ / shares			$ 20.09
Fair value of RSUs vested			$ 17,000
Award period	3 years		3 years
Performance-Based \| 2022 Award Year
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average grant date fair value (in usd per share) \| $ / shares		$ 23.05
Fair value of RSUs vested		$ 27,000
Award period	3 years	3 years
Performance-Based \| 2023 Award Year
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of RSUs vested	$ 42,000
Award period	3 years
Performance-Based \| Minimum \| 2021 Award Year
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Payout percentage of target award			0.00%
Post-vesting holding period			1 year
Performance-Based \| Minimum \| 2022 Award Year
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Payout percentage of target award		0.00%
Post-vesting holding period		1 year
Performance-Based \| Minimum \| 2023 Award Year
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Payout percentage of target award	0.00%
Post-vesting holding period	1 year
Performance-Based \| Maximum \| 2021 Award Year
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Payout percentage of target award			200.00%
Performance-Based \| Maximum \| 2022 Award Year
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Payout percentage of target award	200.00%	200.00%
Performance-Based \| Maximum \| 2023 Award Year
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Payout percentage of target award	200.00%
Time-Vested
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average grant date fair value (in usd per share) \| $ / shares	$ 31.68
Time-Vested \| 2021 Award Year
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period			3 years
Weighted-average grant date fair value (in usd per share) \| $ / shares			$ 20.61
Fair value of RSUs vested			$ 11,000
Number of anniversaries of the grant date \| Anniversary			3
Time-Vested \| 2022 Award Year
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period		3 years
Weighted-average grant date fair value (in usd per share) \| $ / shares		$ 25.13
Fair value of RSUs vested		$ 16,000
Number of anniversaries of the grant date \| Anniversary		3
Time-Vested \| 2023 Award Year
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	3 years
Fair value of RSUs vested	$ 19,000
Number of anniversaries of the grant date \| Anniversary	3
Time-Vested \| Minimum \| 2021 Award Year
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period			1 year
Time-Vested \| Minimum \| 2022 Award Year
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period		1 year
Time-Vested \| Minimum \| 2023 Award Year
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	1 year
Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options granted (in shares) \| shares	0
2021 Equity Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares of common stock authorized for issuance \| shares	8,300,000
Number of shares remaining available for grant (shares reserve) \| shares	3,600,000
Equity Compensation Plans
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum contractual term for all awards	10 years
Unrecognized compensation expense	$ 26
Period for recognition	1 year 9 months 18 days
Equity Compensation Plans \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	1 year
Equity Compensation Plans \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	3 years
Amended and Restated Radian Group Inc. Employee Stock Purchase Plan \| ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected vesting or offering term	6 months
Discount percentage from market price	15.00%
Shares issued to employees under ESPP plans (in shares) \| shares	100,000	100,000	100,000
ESPP, number of shares available for issuance \| shares				1,300,000