FAIR VALUE MEASUREMENTS: (Tables)

12 Months Ended

Dec. 31, 2015

Fair Value Measurements

Schedule of financial assets and liabilities measured at fair value

	Estimated Fair Value December 31, 2015
	Total		Input Levels Used
	Fair Value		Level 1		Level 2		Level 3
Cash and equivalents	$	126,145	$	126,145	$	—	$	—
Available for sale securities		134,501		2,430		132,071		—
Foreign currency forward contracts		(2,626)		—		(2,626)		—
Commodity futures contracts, net		271		271		—		—
Trading securities		60,584		60,584		—		—
Total assets measured at fair value	$	318,875	$	189,430	$	129,445	$	—

	Estimated Fair Value December 31, 2014
	Total		Input Levels Used
	Fair Value		Level 1		Level 2		Level 3
Cash and equivalents	$	100,108	$	100,108	$	—	$	—
Available for sale securities		131,347		2,446		128,901		—
Foreign currency forward contracts		(1,939)		—		(1,939)		—
Commodity futures contracts, net		(737)		(737)		—		—
Trading securities		71,682		71,682		—		—
Total assets measured at fair value	$	300,461	$	173,499	$	126,962	$	—

Summary of the aggregate fair value, gross unrealized gains, gross unrealized losses, realized losses and amortized cost basis of investment portfolio by major security type

	December 31, 2015
	Amortized		Fair		Unrealized				Realized
Available for Sale:	Cost		Value		Gains		Losses		Losses
Municipal bonds	$	34,021	$	33,977	$	—	$	(44)	$	—
Corporate bonds		95,286		94,403		—		(883)		—
Government securities		2,430		2,430		—		—		—
Certificates of deposit		3,692		3,676		—		(16)		—
Mutual funds		20		15		—		(5)		—
	$	135,449	$	134,501	$	—	$	(948)	$	—

	December 31, 2014
	Amortized		Fair		Unrealized				Realized
Available for Sale:	Cost		Value		Gains		Losses		Losses
Municipal bonds	$	51,797	$	51,804	$	7	$	—	$	—
Corporate bonds		72,587		72,075		—		(512)		—
Government securities		2,450		2,446		—		(4)		—
Certificates of deposit		5,014		5,007		—		(7)		—
Mutual funds		20		15		—		(5)		—
	$	131,868	$	131,347	$	7	$	(528)	$	—