Consolidated Statements of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash flows from operating activities:
Net (loss) income	$ (8.4)	$ 63.6	$ 50.3
Adjustments to reconcile net (loss) income to net cash provided by operating activities:
Amortization and depreciation	27.3	31.9	33.8
Share-based payments expense	16.9	18.3	12.3
Deferred income tax benefit, net	(26.5)	(12.6)	(17.9)
Net realized investment (gains) loss	(80.0)	72.0	(39.3)
Undistributed earnings from alternative investment portfolio	(19.9)	(19.8)	(49.5)
Loss on disposals of long-lived assets, net	7.2	0.3	2.1
Impairment of goodwill	15.6	0.0	0.0
Change in:
Accrued investment income	1.5	(3.5)	(2.7)
Receivables	(460.4)	(557.5)	(602.7)
Deferred acquisition costs	7.0	(7.3)	(11.5)
Ceded unearned premiums	(87.8)	(47.6)	(4.2)
Reserves for losses and loss adjustment expenses	509.0	338.3	653.9
Unearned premiums	111.7	76.4	85.5
Ceded reinsurance payable and funds held	246.5	226.5	88.8
Income taxes	8.9	(6.1)	(8.9)
Accrued underwriting expenses and other liabilities	(5.4)	110.2	(23.5)
Other, net	(79.9)	18.2	(1.5)
Cash provided by operating activities	183.3	301.3	165.0
Cash flows from investing activities:
Sales of fixed maturity investments	1,394.3	1,259.1	1,433.3
Maturities and mandatory calls of fixed maturity investments	522.2	418.6	678.3
Sales of equity securities	374.7	238.9	201.1
Sales of other investments	83.1	101.8	95.5
Purchases of fixed maturity investments	(1,859.1)	(1,936.0)	(2,464.1)
Purchases of equity securities	(61.2)	(170.5)	(157.7)
Purchases of other investments	(63.7)	(42.6)	(39.0)
Change in foreign regulatory deposits and voluntary pools	0.0	13.0	(7.2)
Change in short-term investments	(490.4)	(132.2)	306.7
Settlements of foreign currency exchange forward contracts	0.3	(1.5)	(2.9)
Acquisition of Maybrooke, net of cash acquired	0.0	0.0	(105.2)
Cash acquired with acquisition of Ariscom	0.0	15.6	0.0
Purchases of fixed assets	(29.9)	(32.2)	(30.6)
Other, net	(13.1)	(0.3)	(29.5)
Cash used in investing activities	(142.8)	(268.3)	(121.3)
Cash flows from financing activities:
Additional long-term borrowings	0.0	0.0	125.0
Payment on note payable	(0.6)	0.0	0.0
Activity under stock incentive plans	1.9	1.6	1.4
Repurchase of Company's common shares	0.0	(31.7)	(45.2)
Payment of cash dividends to common shareholders	(43.1)	(37.5)	(33.2)
Cash (used in) provided by financing activities	(41.8)	(67.6)	48.0
Effect of exchange rate changes on cash	(0.1)	(2.8)	(1.1)
Change in cash	(1.4)	(37.4)	90.6
Cash, beginning of year	139.2	176.6	86.0
Cash, end of period	$ 137.8	$ 139.2	$ 176.6