Reinsurance - Variable Interest Entity (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2020	Dec. 31, 2019
Home Re special purpose insurers
Effects of Reinsurance [Line Items]
Amortization period excess of loss reinsurance coverage	10 years
Term of mortgage insurance-linked notes	10 years
Remaining First Layer Retention	$ 351,735	$ 353,415
Remaining Excess of Loss Reinsurance Coverages	$ 426,489	531,978
Percent of total trust assets invested in cash or direct U.S. federal government obligations	99.50%
Home Re 2018-1
Effects of Reinsurance [Line Items]
Remaining First Layer Retention	$ 166,573	167,779
Remaining Excess of Loss Reinsurance Coverages	218,343	260,957
Total VIE Assets	218,343	269,451
Home Re 2019-1
Effects of Reinsurance [Line Items]
Remaining First Layer Retention	185,162	185,636
Remaining Excess of Loss Reinsurance Coverages	208,146	271,021
Total VIE Assets	$ 208,146	$ 283,150