Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2012

Fair Value Disclosures [Abstract]

Financial Assets And Liabilities Measured At Fair Value On A Recurring Basis

Financial assets and liabilities measured at fair value on a recurring basis at December 31, 2012 and 2011 consisted of the following:

(In thousands)	Fair Value Measurements
At December 31, 2012	Total		Level 1		Level 2		Level 3
Mutual funds	$	1,817	$	1,817	$	—	$	—
Investments
Federal agency notes	$	124,715	$	—	$	124,715	$	—
Commercial paper	$	137,268	$	—	$	137,268	$	—

(In thousands)	Fair Value Measurements
At December 31, 2011	Total		Level 1		Level 2		Level 3
Mutual funds	$	1,279	$	1,279	$	—	$	—
Investments
Federal agency notes	$	18,621	$	—	$	18,621	$	—
Commercial paper	$	30,912	$	—	$	30,912	$	—

Financial Assets And Liabilities Measured At Fair Value On A Nonrecurring Basis

Financial assets and liabilities measured at fair value on a nonrecurring basis at December 31, 2012 and 2011 consisted of the following:

(In thousands)	Fair Value Measurements
At December 31, 2012	Total		Level 1		Level 2		Level 3
1.875 % Convertible debentures	$	166,292	$	—	$	166,292	$	—
1.75% Convertible debentures	$	302,466	$	—	$	302,466	$	—
Exempt facility revenue bonds	$	29,968	$	—	$	—	$	29,968

(In thousands)	Fair Value Measurements
At December 31, 2011	Total		Level 1		Level 2		Level 3
1.875% Convertible debentures	$	160,256	$	—	$	160,256	$	—
Exempt facility revenue bonds	$	27,269	$	—	$	—	$	27,269