Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Cash flows from operating activities:
Net income (loss)	$ 122.0	$ (53.2)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Amortization and depreciation	28.5	24.7
Share-based payments expense	6.4	7.7
Deferred income tax benefit, net	(14.4)	(16.5)
Net realized investment (gains) losses	(32.5)	24.0
Undistributed earnings from alternative investment portfolio	(74.8)	1.6
Loss on disposals of long-lived assets, net	1.7	0.4
Change in:
Accrued investment income	0.9	3.5
Receivables	30.2	(67.4)
Deferred acquisition costs	(12.0)	(11.7)
Ceded unearned premiums	2.3	(120.5)
Reserves for losses and loss adjustment expenses	36.5	267.6
Unearned premiums	77.3	176.8
Ceded reinsurance payable and funds held	(176.3)	(104.2)
Income taxes	(1.0)	(22.2)
Accrued underwriting expenses and other liabilities	42.5	(0.8)
Other, net	3.5	(8.4)
Cash provided by (used in) operating activities	40.8	101.4
Cash flows from investing activities:
Sales of fixed maturity investments	786.4	977.5
Maturities and mandatory calls of fixed maturity investments	591.1	410.3
Sales of equity securities	36.9	18.2
Sales of other investments	81.1	95.5
Purchases of fixed maturity investments	(1,511.9)	(1,659.3)
Purchases of equity securities	(5.3)	(68.3)
Purchases of other investments	(40.1)	(24.5)
Change in foreign regulatory deposits and voluntary pools	36.2	(0.5)
Change in short-term investments	32.3	297.8
Settlements of foreign currency exchange forward contracts	(9.7)	9.1
Proceeds from sale of Trident assets	0.0	38.0
Sale (Purchases) of fixed assets, net	16.0	(15.8)
Other, net	37.6	2.7
Cash (used in) provided by investing activities	50.6	80.7
Cash flows from financing activities:
Payment of long-term debt	0.0	(125.0)
Issuance of preferred shares, net of issuance costs	0.0	144.0
Activity under stock incentive plans	1.2	1.4
Payment of cash dividends to preferred shareholders	(7.9)	(2.0)
Payment of cash dividends to common shareholders	(32.7)	(32.2)
Cash used in financing activities	(39.4)	(13.8)
Effect of exchange rate changes on cash	1.2	(5.7)
Change in cash	53.2	162.6
Cash, beginning of year	148.8	137.8
Cash, end of period	$ 202.0	$ 300.4