Statutory Information - Narrative (Details)	12 Months Ended
	Dec. 31, 2021 USD ($) jurisdiction	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Statutory capital requirements [Abstract]
Number of jurisdictions with risk-to-capital requirements | jurisdiction	16
Maximum permitted risk-to-capital ratio commonly applied	25 to 1
Risk to capital ratio of combined insurance operations at end of period	9.5 to 1
Risk-to-capital ratio on combined insurance operations	9.5
Statutory net income	$ 295,811,000	$ 65,201,000	$ 305,857,000
Statutory policyholders' surplus	$ 1,220,714,000	$ 1,339,509,000	$ 1,619,069,000
Insurance Subsidiaries
Statutory capital requirements [Abstract]
Percentage of statutory policyholders surplus used to determine maximum allowable dividends	10.00%
Adjusted statutory net income measurement period	3 years
Adjusted statutory net income dividend payment measurement period	2 years
Maximum
Statutory capital requirements [Abstract]
Risk to capital ratio	25
Mortgage Guaranty Insurance Corporation
Statutory capital requirements [Abstract]
Risk to capital ratio at end of period	9.5 to 1
Risk to capital ratio	9.5
Amount of policyholders position above or below required MPP	$ 3,400,000,000
Amount of required MPP	1,900,000,000
Increase in contingency reserve	534,000,000
Statutory net income	290,000,000
Statutory policyholders' surplus	$ 1,217,000,000