FAIR VALUE MEASUREMENTS: (Tables)

12 Months Ended

Dec. 31, 2014

Fair Value Measurements

Schedule of financial assets and liabilities measured at fair value

	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	$	—

	Estimated Fair Value December 31, 2013
	Total		Input Levels Used
	Fair Value		Level 1		Level 2		Level 3
Cash and equivalents	$	88,283	$	88,283	$	—	$	—
Available for sale securities		118,647		—		118,647		—
Foreign currency forward contracts		(684)		—		(684)		—
Commodity futures contracts, net		(130)		(130)		—		—
Trading securities		63,215		63,215		—		—
Total assets measured at fair value	$	269,331	$	151,368	$	117,963	$	—

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, 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)	$	—

	December 31, 2013
	Amortized		Fair		Unrealized				Realized
Available for Sale:	Cost		Value		Gains		Losses		Losses
Municipal bonds	$	75,488	$	75,622	$	134	$	—	$	—
Corporate bonds		37,258		37,214		—		(44)		—
Certificates of deposit		5,796		5,794				(2)
Mutual funds		20		17		—		(3)		—
	$	118,562	$	118,647	$	134	$	(49)	$	—