Condensed Consolidated Balance Sheets - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Investments:
Fixed maturities available-for-sale, at fair value (amortized cost: 2023 - $2,969.8, 2022 - $3,016.4; allowance for expected credit losses: 2023 - $2.7, 2022 - $2.8)	$ 2,664.4	$ 2,675.5
Commercial mortgage loans (cost: 2023 - $159.9, 2022 - $159.9; allowance for expected credit losses: 2023 - $0.2, 2022 - $0.2)	159.7	159.7
Equity securities, at fair value (cost: 2023 - $48.7; 2022 - $54.7)	44.2	43.9
Other investments (cost: 2023 - $323.0; 2022 - $323.2)	323.0	323.2
Short-term investments, at fair value (amortized cost: 2023 - $694.5; 2022 - $449.4)	694.6	449.6
Total investments	3,885.9	3,651.9
Cash	36.4	50.2
Accrued investment income	18.8	18.6
Premiums receivable	271.1	292.0
Reinsurance recoverables	3,016.9	3,029.1
Goodwill	118.6	118.6
Current income taxes receivable, net	47.2	44.9
Deferred tax asset, net	93.5	101.2
Deferred acquisition costs, net	103.9	107.0
Ceded unearned premiums	367.8	375.5
Operating lease right-of-use assets	54.8	57.7
Other assets	189.2	121.5
Assets held-for-sale	0.0	2,066.2
Total assets	8,204.1	10,034.4
Liabilities and Shareholders' Equity
Reserves for losses and loss adjustment expenses	5,184.1	5,051.6
Unearned premiums	994.3	1,039.9
Accrued underwriting expenses and other liabilities	92.5	121.3
Ceded reinsurance payable, net	174.7	158.7
Funds held	51.8	50.0
Senior unsecured fixed rate notes	140.5	140.5
Junior subordinated debentures	258.7	258.6
Operating lease liabilities	63.0	66.4
Liabilities held-for-sale	0.0	1,914.5
Total liabilities	6,959.6	8,801.5
Commitments and contingencies (Note 14)
Shareholders' equity:
Preferred shares and additional paid-in capital - $1.00 par, 30,000,000 shares authorized; 6,000 and 6,000 shares issued at March 31, 2023 and December 31, 2022, respectively; liquidation preference $25,000	144.0	144.0
Common shares - $1.00 par, 500,000,000 shares authorized; 46,469,201 and 46,379,297 shares issued at March 31, 2023 and December 31, 2022, respectively	46.5	46.4
Additional paid-in capital	1,396.6	1,395.4
Treasury shares (11,318,339 and 11,318,339 shares at March 31, 2023 and December 31, 2022, respectively)	(455.1)	(455.1)
Retained earnings	370.9	407.3
Accumulated other comprehensive loss, net of taxes	(258.4)	(305.1)
Total shareholders' equity	1,244.5	1,232.9
Total liabilities and shareholders' equity	$ 8,204.1	$ 10,034.4