Share-Based Awards (Details - Options) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Summary Of Option Activity [Abstract]
Total intrinsic value of options exercised (in millions of U.S. dollars)	$ 8.5	$ 8.7	$ 24.8
Proceeds from option exercises (in millions of U.S. dollars)	$ 9.8	$ 14.7	$ 49.6
Weighted average remaining contractual term	4 years 2 months
Aggregate intrinsic value of options outstanding, exercisable, vested and expected to vest	$ 18.1
Activity related to share options
Outstanding at January 1, 2015	410,347
Exercised	(142,429)	(225,329)	(819,764)
Outstanding at December 31, 2015	267,918	410,347
Options exercisable at December 31, 2015	267,918
Options vested and expected to vest at December 31, 2015	267,918
The weighted average exercise price is as follows:
Outstanding at January 1, 2015	$ 71.55
Exercised	70.47
Outstanding at December 31, 2015	72.13	$ 71.55
Options exercisable at December 31, 2015	72.13
Options vested and expected to vest at December 31, 2015	$ 72.13