Fair Value Measurement (Tables)

6 Months Ended

Jun. 30, 2016

Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]

The following tables summarize our cash equivalents by significant investment categories (in thousands):



	Fair Value Measurement at Reporting Date Using
June 30, 2016	Level 1		Level 2		Level 3		Total
Cash equivalents
Money market funds	$	30,082	$	—	$	—	$	30,082
Commercial paper	4,994		—		—		4,994
Total assets	$	35,076	$	—	$	—	$	35,076



December 31, 2015
Cash equivalents
Money market funds	$	62,024	$	—	$	—	$	62,024
Total assets	$	62,024	$	—	$	—	$	62,024



June 30, 2015
Cash equivalents
Money market funds	$	23,975	$	—	$	—	$	23,975
Total assets	$	23,975	$	—	$	—	$	23,975

Schedule of Cash and Cash Equivalents [Table Text Block]

A reconciliation of cash equivalents to consolidated cash and cash equivalents is as follows:



(in thousands)	June 30, 2016		December 31, 2015		June 30, 2015
Cash equivalents	$	35,076	$	62,024	$	23,975
Cash	126,142		190,812		164,172
Total cash and cash equivalents	$	161,218	$	252,836	$	188,147

Fair Value Measurements, Nonrecurring [Table Text Block]

The carrying values and estimated fair values of our financial instruments that are not required to be recorded at fair value in the condensed consolidated balance sheets are as follows:



		June 30, 2016				December 31, 2015				June 30, 2015
(in thousands)	Fair Value Hierarchy	Carrying Value		Fair Value		Carrying Value		Fair Value		Carrying Value		Fair Value
Assets:
Held-to-maturity marketable securities	Level 1	$	77,612	$	77,678	$	105,695	$	105,336	$	88,068	$	88,075
Liabilities (including current maturities):
2019 Notes¹	Level 3	$	160,000	$	167,210	$	160,000	$	165,731	$	200,000	$	212,648
Credit Agreement loan¹	Level 3	97,500		97,409		100,000		99,375		70,000		69,387

¹The fair values of the 2019 Notes and Credit Agreement (defined in Note 10) loan are based on borrowing rates available to us for long-term debt with similar terms, average maturities, and credit risk.