Fair Value Measurement (Tables)

9 Months Ended

Sep. 30, 2013

Fair Value Disclosures [Abstract]

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

The following tables summarize assets and liabilities measured at fair value in the condensed consolidated balance sheets on a recurring basis for each of the fair value levels:

September 30, 2013	Fair Value Measurement at Reporting Date Using
(in thousands)	Level 1		Level 2		Level 3		Total
Cash equivalents
Money market funds	$	113,220	$	—	$	—	$	113,220
Total assets	$	113,220	$	—	$	—	$	113,220

December 31, 2012	Fair Value Measurement at Reporting Date Using
(in thousands)	Level 1		Level 2		Level 3		Total
Cash equivalents
Money market funds	$	201,542	$	—	$	—	$	201,542
Held-to-maturity commercial paper	5,000		—		—		5,000
Total assets	$	206,542	$	—	$	—	$	206,542

September 30, 2012	Fair Value Measurement at Reporting Date Using
(in thousands)	Level 1		Level 2		Level 3		Total
Cash equivalents
Money market funds	$	185,586	$	—	$	—	$	185,586
Held-to-maturity commercial paper	14,495		—		—		14,495
Total assets	$	200,081	$	—	$	—	$	200,081

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)	September 30, 2013		December 31, 2012		September 30, 2012
Cash equivalents	$	113,220	$	206,542	$	200,081
Cash	99,243		115,448		87,241
Total cash and cash equivalents	$	212,463	$	321,990	$	287,322

Fair Value Measurements, Nonrecurring [Table Text Block]

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

		September 30, 2013				December 31, 2012				September 30, 2012
(in thousands)	Fair Value Hierarchy	Carrying Value		Fair Value		Carrying Value		Fair Value		Carrying Value		Fair Value
Assets:
Held-to-maturity marketable securities1	Level 1	$	86,906	$	86,594	$	111,430	$	111,525	$	84,987	$	85,133
Liabilities (including current maturities):
Senior notes payable2	Level 3	$	200,000	$	226,110	$	208,333	$	243,118	$	208,333	$	243,219
Credit Agreement loan2	Level 3	70,000		70,166		70,000		70,444		—		—

¹Held-to-maturity marketable securities are periodically assessed for other-than-temporary impairment.

²The fair values of the senior notes payable and Credit Agreement (as defined under “Credit Agreement” in “Item 2. Management’s Discussion and Analysis of Financial Condition and Results of Operations”) loan are based on borrowing rates available to us for long-term loans with similar terms, average maturities, and credit risk.