XML 64 R49.htm IDEA: XBRL DOCUMENT v3.3.1.900
Fair Value Measurements (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Fair Value Measurements    
Marketable securities $ 286,668 $ 415,273
Fair Value of Financial Instruments    
Fair value of long-term debt 1,939,800 1,813,100
Carrying amount of long-term debt 1,948,803 1,745,811
Auction Rate Securities    
Changes in assets measured at fair value on a recurring basis using significant unobservable inputs (level 3)    
Balance at the beginning of the period 2,309  
Total realized and unrealized gains or (losses) Included in other comprehensive income 12  
Balance at the end of the period 2,321  
Recurring | Fair value    
Fair Value Measurements    
Marketable securities 286,668  
Cash, Cash Equivalents and Restricted Cash 211,251 143,857
Other Assets 2,321 2,309
Total Assets Measured at Fair Value 500,240 561,439
Recurring | Bonds and bond funds | Fair value    
Fair Value Measurements    
Marketable securities 286,637 410,163
Recurring | Asset-backed Securities | Fair value    
Fair Value Measurements    
Marketable securities 31 415,273
Recurring | Commercial Paper | Fair value    
Fair Value Measurements    
Marketable securities   5,110
Recurring | Level 1    
Fair Value Measurements    
Cash, Cash Equivalents and Restricted Cash 211,251 143,857
Total Assets Measured at Fair Value 211,251 143,857
Recurring | Level 2    
Fair Value Measurements    
Marketable securities 286,668  
Total Assets Measured at Fair Value 286,668 415,273
Recurring | Level 2 | Bonds and bond funds    
Fair Value Measurements    
Marketable securities 286,637 410,163
Recurring | Level 2 | Asset-backed Securities    
Fair Value Measurements    
Marketable securities 31 415,273
Recurring | Level 2 | Commercial Paper    
Fair Value Measurements    
Marketable securities   5,110
Recurring | Level 3    
Fair Value Measurements    
Other Assets 2,321 2,309
Total Assets Measured at Fair Value $ 2,321 $ 2,309