Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Cash flows from operating activities:
Net (loss) income	$ (54.8)	$ 94.9
Adjustments to reconcile net (loss) income to net cash provided by operating activities:
Amortization and depreciation	24.7	20.4
Share-based payments expense	7.7	11.7
Deferred income tax benefit, net	(23.2)	(2.2)
Net realized investment losses (gains)	21.7	(58.3)
Undistributed earnings (loss) from alternative investment portfolio	1.6	(19.4)
Loss on disposals of long-lived assets, net	0.4	0.0
Change in:
Accrued investment income	3.5	(0.5)
Receivables	(65.1)	(282.6)
Deferred acquisition costs	(11.7)	7.5
Ceded unearned premiums	(120.5)	(147.1)
Reserves for losses and loss adjustment expenses	267.6	194.9
Unearned premiums	176.8	197.7
Ceded reinsurance payable and funds held	(102.2)	204.8
Income taxes	(12.8)	7.9
Accrued underwriting expenses and other liabilities	(7.4)	8.5
Other, net	(4.9)	(42.5)
Cash provided by operating activities	101.4	195.7
Cash flows from investing activities:
Sales of fixed maturity investments	977.5	1,046.3
Maturities and mandatory calls of fixed maturity investments	410.3	292.2
Sales of equity securities	18.2	66.3
Sales of other investments	95.5	67.7
Purchases of fixed maturity investments	(1,659.3)	(1,535.0)
Purchases of equity securities	(68.3)	(49.9)
Purchases of other investments	(24.5)	(54.6)
Change in foreign regulatory deposits and voluntary pools	(0.5)	2.3
Change in short-term investments	297.8	0.0
Settlements of foreign currency exchange forward contracts	9.1	(1.2)
Proceeds from sale of Trident assets	38.0	0.0
Purchases of fixed assets	(15.8)	(22.9)
Other, net	2.7	29.6
Cash provided by (used in) investing activities	80.7	(159.2)
Cash flows from financing activities:
Payment of long-term debt	(125.0)	(0.6)
Issuance of preferred shares, net of issuance costs	144.0	0.0
Activity under stock incentive plans	1.4	1.4
Payment of cash dividends to preferred shareholders	(2.0)	0.0
Payment of cash dividends to common shareholders	(32.2)	(32.5)
Cash used in financing activities	(13.8)	(31.7)
Effect of exchange rate changes on cash	(5.7)	1.1
Change in cash	162.6	5.9
Cash, beginning of year	137.8	139.2
Cash, end of period	$ 300.4	$ 145.1