BENEFIT PLANS: (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
BENEFIT PLANS:
Number of expatriate non-contributory defined benefit pension plans	2
Post retirement defined benefit plans
Defined benefit plan, net periodic benefit cost
Service cost	$ 0.9	$ 1.0
Interest cost	0.9	0.8
Expected return on plan assets	(2.7)	(2.5)
Amortization of net actuarial loss	(0.2)	(0.6)
Amortization of net loss (gain)	0.1	0.1
Net periodic benefit costs	(1.0)	(1.2)
Post-retirement Health Care Plan
Defined benefit plan, net periodic benefit cost
Interest cost	1.0	1.2
Amortization of net loss (gain)	(0.2)
Net periodic benefit costs	$ 0.8	$ 1.2