SHARE INCENTIVE PLANS: (Details 3) - shares	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Employee Share Purchase Plan
Weighted average assumptions
Expected volatility (as a percent)	38.10%	45.10%
Risk-free interest rate (as a percent)	0.09%	0.06%
Expected life, years	6 months	6 months
Share options
Weighted average assumptions
Expected volatility (as a percent)		56.10%
Risk-free interest rate (as a percent)		1.98%
Expected life, years		5 years 9 months 7 days
Estimated forfeiture rate (as a percent)		6.73%
Options Granted (in shares)	0