SCHEDULE VI SUPPLEMENTAL INFORMATION FOR PROPERTY AND CASUALTY INSURANCE UNDERWRITERS (Details) - Ark $ in Millions	12 Months Ended
	Dec. 31, 2021 USD ($)
SUPPLEMENTAL INFORMATION FOR PROPERTY AND CASUALTY INSURANCE UNDERWRITERS
Deferred acquisition costs	$ 100.8
Reserves for Unpaid Claims and Claims Adjustment Expenses	894.7
Discount, if any, deducted in Column C	0.0
Unearned Premiums	495.9
Earned Premiums	637.3
Net investment income	2.9
Current Year	336.3
Prior Year	(21.5)
Amortization of deferred policy acquisition costs	111.3
Paid Claims and Claims Adjustment Expenses	105.5
Premiums written	$ 859.1