Quarterly Results (Tables)

12 Months Ended

Dec. 31, 2014

Quarterly Results [Abstract]

Quarterly data

The following table sets forth selected unaudited quarterly data for the periods shown as revised (U.S. dollars in millions, except per share amounts):

	2013								2014
	1st Quarter		2nd Quarter		3rd Quarter		4th Quarter		1st Quarter		2nd Quarter		3rd Quarter		4th Quarter
Revenue	$	541.3	$	671.3	$	908.3	$	1,055.8	$	671.1	$	650.0	$	638.8	$	609.6
Gross profit		451.3		560.0		768.5		891.1		564.4		494.0		529.5		503.1
Operating income		82.6		114.6		168.3		188.6		101.2		54.7		105.0		91.3
Net income		54.3		74.4		110.9		125.3		54.9		19.5		68.3		46.5
Net income per share:
Basic		0.93		1.27		1.89		2.13		0.93		0.33		1.15		0.79
Diluted		0.90		1.22		1.80		2.02		0.90		0.32		1.12		0.77