FAIR VALUE MEASUREMENTS

6 Months Ended

Jun. 30, 2014

Fair Value Disclosures [Abstract]

FAIR VALUE MEASUREMENTS

4. FAIR VALUE MEASUREMENTS

Accounting standards require that assets and liabilities carried at fair value will be classified and disclosed in one of the following three categories:

Level 1: Quoted market prices in active markets for identical assets or liabilities.

Level 2: Observable market based inputs or unobservable inputs that are corroborated by market data.

Level 3: Unobservable inputs that are not corroborated by market data.

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

We hold our short-term investments in an investment fund consisting of investment grade money market instruments of governmental and private issuers, which are classified as short-term investments. Level 1 inputs are quoted prices (unadjusted) for identical assets or liabilities in active markets. These items are traded with sufficient frequency and volume to provide pricing on an ongoing basis. The fair values of the shares of these funds are based on observable market prices, and therefore, have been categorized in Level 1 in the fair value hierarchy. Level 2 inputs reflect quoted prices for identical assets or liabilities that are not active. These items may not be traded daily; examples include corporate bonds and U.S. government agencies. There have been no reclassifications for assets between Level 1 and Level 2 investments. We hold no Level 3 investments. Investments included in other assets, which relate to the liability for the Officers’ Deferred Compensation Plan, consist mainly of multiple investment funds that are highly liquid and diversified.

Cash, accounts receivable, accounts payable and accrued liabilities, and our revolving credit facility debt all had fair values approximating their carrying amounts at June 30, 2014 and December 31, 2013. Our determination of the estimated fair value of our Senior Notes and our revolving credit facility debt is derived using Level 2 inputs, including quoted market indications of similar publicly-traded debt. The fair value of our Senior Notes, based on quoted market prices, was $510.6 million and $323.3 million at June 30, 2014 and December 31, 2013, respectively.