FAIR VALUE MEASUREMENTS (Tables)

6 Months Ended

Jun. 30, 2014

Fair Value Disclosures [Abstract]

Summary of Valuation of Investments and Financial Instruments Pricing Levels

The following table summarizes the valuation of our investments and financial instruments by the above pricing levels as of the valuation dates listed:

			June 30, 2014
	Total		(Level 1)		(Level 2)
Investments:
Money market mutual funds	$	69,048	$	69,048	$	—
Municipal bonds and notes		1,504		—		1,504
Corporate bonds and notes		80,729		—		80,729
		151,281		69,048		82,233
Deferred compensation plan assets		2,359		2,359		—
Total	$	153,640	$	71,407	$	82,233

			December 31, 2013
	Total		(Level 1)		(Level 2)
Investments:
Money market mutual funds	$	18,470	$	18,470	$	—
Commercial paper		2,999		—		2,999
Municipal bonds and notes		1,499		—		1,499
Corporate bonds and notes		77,633		—		77,633
		100,601		18,470		82,131
Deferred compensation plan assets		2,109		2,109		—
Total	$	102,710	$	20,579	$	82,131