Insurance Company WNFIC - Additional Information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020 USD ($) Reinsurer	Dec. 31, 2019 USD ($)	Sep. 30, 2020
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Ceded rate of premiums under insurance program	100.00%
Premiums written net	$ 728,093	$ 697,059
Ceded unpaid loss	43,500	58,500
Prepaid reinsurance premiums	377,615	366,021
Increase (decrease) in loss and loss adjustment expense reserve	0	0
Reserve for losses and loss adjustment expense	$ 43,500	58,500
Number of reinsurers | Reinsurer	2
Wright National Flood Insurance Company
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Ceded rate of premiums under insurance program	100.00%
Expenses and allowance rate received in premiums	30.00%		30.10%
Premiums written net	$ 725,800	694,900
Statutory capital and surplus required	7,500
Statutory capital and surplus	32,600	29,600
Statutory net Income	$ 800	$ 8,100
Preferred stock, dividend rate, percentage	100.00%
Maximum dividend payout that may be made without prior approval	$ 3,300
Wright National Flood Insurance Company | Maximum
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Preferred stock, dividend rate, percentage	10.00%