Segment Information (Tables)

6 Months Ended

Jun. 30, 2016

Segment Reporting [Abstract]

Summary of segment results

The following tables provide a summary of the segment results:

Three Months Ended June 30, 2016	North American  Insurance			Global Markets Insurance			Reinsurance			Total
Gross premiums written	$	508.4		$	125.4		$	166.5		$	800.3
Net premiums written	330.8			88.2			159.1			578.1
Net premiums earned	329.6			94.1			179.2			602.9
Net losses and loss expenses	(209.9		)	(61.1		)	(94.4		)	(365.4		)
Acquisition costs	(37.4		)	(16.3		)	(33.7		)	(87.4		)
General and administrative expenses	(56.8		)	(31.5		)	(16.4		)	(104.7		)
Underwriting income (loss)	25.5			(14.8		)	34.7			45.4
Other insurance-related income	0.9			—			4.3			5.2
Other insurance-related expenses	(0.6		)	—			(1.1		)	(1.7		)
Segment income (loss)	25.8			(14.8		)	37.9			48.9
Net investment income										55.8
Net realized investment gains										74.5
Amortization of intangible assets										(2.5		)
Interest expense										(19.9		)
Foreign exchange gain										2.9
Income before income taxes										$	159.7
Loss and loss expense ratio	63.7		%	64.9		%	52.7		%	60.6		%
Acquisition cost ratio	11.4		%	17.3		%	18.8		%	14.5		%
General and administrative expense ratio	17.2		%	33.5		%	9.1		%	17.4		%
Expense ratio	28.6		%	50.8		%	27.9		%	31.9		%
Combined ratio	92.3		%	115.7		%	80.6		%	92.5		%

Three Months Ended June 30, 2015	North American  Insurance			Global Markets Insurance			Reinsurance			Total
Gross premiums written	$	517.5		$	135.0		$	173.5		$	826.0
Net premiums written	372.2			69.3			162.2			603.7
Net premiums earned	328.6			102.6			215.2			646.4
Net losses and loss expenses	(237.7		)	(65.8		)	(128.0		)	(431.5		)
Acquisition costs	(34.2		)	(24.3		)	(42.1		)	(100.6		)
General and administrative expenses	(58.2		)	(30.7		)	(19.5		)	(108.4		)
Underwriting (loss) income	(1.5		)	(18.2		)	25.6			5.9
Other insurance-related income	0.9			—			—			0.9
Other insurance-related expenses	(0.6		)	(0.6		)	—			(1.2		)
Segment (loss) income	(1.2		)	(18.8		)	25.6			5.6
Net investment income										42.8
Net realized investment losses										(20.2		)
Amortization of intangible assets										(2.8		)
Interest expense										(14.5		)
Foreign exchange loss										(1.3		)
Income before income taxes										$	9.6
Loss and loss expense ratio	72.4		%	64.1		%	59.5		%	66.8		%
Acquisition cost ratio	10.4		%	23.7		%	19.6		%	15.6		%
General and administrative expense ratio	17.7		%	29.9		%	9.1		%	16.8		%
Expense ratio	28.1		%	53.6		%	28.7		%	32.4		%
Combined ratio	100.5		%	117.7		%	88.2		%	99.2		%

Six Months Ended June 30, 2016	North American  Insurance			Global Markets Insurance			Reinsurance			Total
Gross premiums written	$	887.5		$	241.0		$	535.3		$	1,663.8
Net premiums written	597.0			175.8			509.3			1,282.1
Net premiums earned	645.9			188.3			348.8			1,183.0
Net losses and loss expenses	(426.2		)	(128.9		)	(182.7		)	(737.8		)
Acquisition costs	(71.3		)	(34.2		)	(70.2		)	(175.7		)
General and administrative expenses	(109.0		)	(60.6		)	(31.5		)	(201.1		)
Underwriting (loss) income	39.4			(35.4		)	64.4			68.4
Other insurance-related income	1.5			—			4.2			5.7
Other insurance-related expenses	(1.3		)	—			(1.5		)	(2.8		)
Segment income	39.6			(35.4		)	67.1			71.3
Net investment income										109.1
Net realized investment gains										93.4
Amortization of intangible assets										(5.0		)
Interest expense										(39.8		)
Foreign exchange gain										5.9
Income before income taxes										$	234.9
Loss and loss expense ratio	66.0		%	68.4		%	52.4		%	62.4		%
Acquisition cost ratio	11.0		%	18.1		%	20.1		%	14.9		%
General and administrative expense ratio	16.9		%	32.1		%	9.0		%	17.0		%
Expense ratio	27.9		%	50.2		%	29.1		%	31.9		%
Combined ratio	93.9		%	118.6		%	81.5		%	94.3		%

Six Months Ended June 30, 2015	North American  Insurance			Global Markets Insurance			Reinsurance			Total
Gross premiums written	$	898.2		$	195.6		$	612.8		$	1,706.6
Net premiums written	669.1			112.2			594.9			1,376.2
Net premiums earned	641.5			152.7			420.7			1,214.9
Net losses and loss expenses	(433.2		)	(86.3		)	(237.2		)	(756.7		)
Acquisition costs	(65.3		)	(31.3		)	(82.7		)	(179.3		)
General and administrative expenses	(117.5		)	(48.7		)	(39.3		)	(205.5		)
Underwriting income (loss)	25.5			(13.6		)	61.5			73.4
Other insurance-related income	1.9			—			—			1.9
Other insurance-related expenses	(1.5		)	(1.6		)	—			(3.1		)
Segment income (loss)	25.9			(15.2		)	61.5			72.2
Net investment income										87.3
Net realized investment gains										24.8
Amortization of intangible assets										(3.4		)
Interest expense										(28.8		)
Foreign exchange loss										(11.2		)
Income before income taxes										$	140.9
Loss and loss expense ratio	67.5		%	56.5		%	56.4		%	62.3		%
Acquisition cost ratio	10.2		%	20.5		%	19.7		%	14.8		%
General and administrative expense ratio	18.3		%	31.9		%	9.3		%	16.9		%
Expense ratio	28.5		%	52.4		%	29.0		%	31.7		%
Combined ratio	96.0		%	108.9		%	85.4		%	94.0		%

Analysis of gross written premium by geographic location

The following table shows an analysis of the Company’s gross premiums written by geographic location of the Company’s subsidiaries and branches. All intercompany premiums have been eliminated.

	Three Months Ended   June 30,				Six Months Ended   June 30,
	2016		2015		2016		2015
United States	$	495.6	$	483.1	$	1,020.0	$	1,019.8
Bermuda	140.9		167.9		285.0		364.5
Asia Pacific	91.4		93.2		193.6		133.3
Europe	65.1		76.3		153.7		180.2
Canada	7.3		5.5		11.5		8.8
Total gross premiums written	$	800.3	$	826.0	$	1,663.8	$	1,706.6

Net premiums earned by segment and line of business

The following table shows the Company's net premiums earned by line of business for each segment for each of the periods indicated.

	Three Months Ended   June 30,				Six Months Ended   June 30,
	2016		2015		2016		2015
North American Insurance:
Professional liability	$	103.1	$	94.7	$	204.6	$	183.5
Casualty	104.3		109.2		201.1		214.1
Programs	43.3		36.7		82.9		70.9
Property	34.6		42.5		68.3		83.9
Other specialty	28.1		17.3		53.3		32.9
Healthcare	16.2		28.2		35.7		56.2
Total	329.6		328.6		645.9		641.5
Global Markets Insurance:
Other specialty	30.2		27.2		61.0		39.9
Casualty	22.2		31.0		45.8		37.0
Professional liability	25.5		26.1		49.0		49.3
Property	16.2		18.3		32.5		26.5
Total	94.1		102.6		188.3		152.7
Reinsurance:
Property	83.4		104.8		167.8		209.1
Casualty	46.7		58.9		92.8		115.8
Specialty	49.1		51.5		88.2		95.8
Total	179.2		215.2		348.8		420.7
Total net premiums earned	$	602.9	$	646.4	$	1,183.0	$	1,214.9