Insurance Company Subsidiary Operations - Effects of Reinsurance on Premiums Written and Earned (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Written
Net premiums	$ 38.3
Earned
Net premiums	26.4
WNFIC
Written
Direct premiums	740.9	$ 747.4
Ceded premiums	(740.9)	(747.4)
Earned
Direct premiums	751.3	732.8
Ceded premiums	(751.3)	$ (732.8)
Quota Share Captive and Excess of Loss Layer Captive
Written
Assumed premiums	65.4
Net premiums	38.3
Earned
Assumed premiums	43.7
Net premiums	26.4
Quota Share Captive
Written
Ceded premiums	(27.1)
Net premiums	38.3
Earned
Ceded premiums	(17.3)
Net premiums	$ 20.6