Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2017		Jun. 30, 2016
Cash flows from operating activities:
Net income	$ 82.7		$ 58.6
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Amortization and depreciation	15.9		17.8
Share-based payments expense	7.6		5.6
Deferred income tax (benefit) provision, net	(4.7)		6.1
Net realized investment and other (gains) losses	(19.1)		4.9
Undistributed earnings from alternative investment portfolio	(32.9)		(10.9)
Loss on disposals of fixed assets, net	1.7		0.1
Change in:
Accrued investment income	(2.1)		0.9
Receivables	(103.9)		(185.3)
Deferred acquisition costs	(13.8)		(11.8)
Ceded unearned premiums	(41.0)		(60.3)
Reserves for losses and loss adjustment expenses	85.4		51.0
Unearned premiums	53.3		66.5
Ceded reinsurance payable and funds held	57.0		138.5
Income taxes	5.9		9.1
Accrued underwriting expenses	(21.7)		(23.6)
Other, net	(33.0)		(35.6)
Cash provided by operating activities	37.3		31.6
Cash flows from investing activities:
Sales of fixed maturity investments	785.8		532.0
Maturities and mandatory calls of fixed maturity investments	335.1		673.3
Sales of equity securities	107.5		93.0
Sales of other investments	65.1		5.5
Purchases of fixed maturity investments	(1,381.7)		(1,119.0)
Purchases of equity securities	(67.5)		(59.6)
Purchases of other investments	(16.8)		(77.1)
Change in foreign regulatory deposits and voluntary pools	(9.5)		2.7
Change in short-term investments	309.9		(13.7)
Settlements of foreign currency exchange forward contracts	0.5		6.8
Acquisition of subsidiaries, net of cash acquired	(105.2)		0.0
Purchases of fixed assets	(10.0)		(22.7)
Other, net	(27.7)		(0.9)
Cash (used in) provided by investing activities	(14.5)		20.3
Cash flows from financing activities:
Additional long-term borrowings	125.0		0.0
Activity under stock incentive plans	0.5		0.2
Repurchase of Company's common shares	(2.8)		(40.0)
Payment of cash dividends to common shareholders	(16.6)		(13.1)
Cash provided by (used in) financing activities	106.1		(52.9)
Effect of exchange rate changes on cash	(0.4)		(0.1)
Change in cash	128.5		(1.1)
Cash, beginning of year	86.0	[1]	121.7
Cash, end of period	$ 214.5		$ 120.6

[1] Derived from audited consolidated financial statements.