XML 64 R43.htm IDEA: XBRL DOCUMENT

CONCENTRATION OF RISK: (Tables)

12 Months Ended

Dec. 31, 2017

CONCENTRATION OF RISK:

Schedule of concentration risk for cash equivalents and short- term investments

								% in one institution
Country		$ in million			% of total cash(1)			of country			of total cash
United States		$	655.1			62.1	%		19.2	%		11.9	%
Switzerland			319.5			30.3	%		60.6	%		18.3	%
Peru			23.5			2.2	%		63.5	%		1.4	%
Mexico			57.2			5.4	%		61.4	%		3.3	%

Total cash and short-term investment		$	1,055.3			100.0	%


(1)	94.9% of the Company's cash is in U.S. dollars.

Schedule of company's largest customers as percentage of accounts receivable and total sales

		2017			2016			2015
Accounts receivable trade as of December 31,
Five largest customers			28.4	%		31.1	%		32.4	%
Largest customer			8.2	%		11.9	%		10.9	%
Total sales in year
Five largest customers			25.1	%		30.4	%		28.0	%
Largest customer			8.8	%		8.4	%		7.7	%