XML 55 R45.htm IDEA: XBRL DOCUMENT v3.8.0.1
Financial Instruments and Fair Value Measurement - Assets measured at fair value and Supplemental fair value information (Details) - USD ($)
$ in Thousands
Dec. 31, 2017
Sep. 30, 2017
Mar. 19, 2015
Supplemental fair value information about long-term fixed-rate debt      
Long-term debt $ 493,168 $ 492,902  
Unsecured senior notes issued March 19, 2015      
Supplemental fair value information about long-term fixed-rate debt      
Debt issued 500,000   $ 500,000
Recurring basis      
Short-term investments:      
Short-term investments 42,541    
Assets:      
Cash and cash equivalents 383,664    
Investments 69,329    
Other current assets 38,226    
Other assets 6,798    
Total assets measured at fair value 540,558    
Liabilities:      
Contingent earnout liability 17,356    
Carrying value      
Supplemental fair value information about long-term fixed-rate debt      
Long-term debt 493,200 492,900  
(Level 1) | Recurring basis      
Short-term investments:      
Short-term investments 26,825    
Assets:      
Cash and cash equivalents 383,664    
Investments 69,329    
Other current assets 38,226    
Other assets 6,798    
Total assets measured at fair value 524,842    
(Level 2)      
Supplemental fair value information about long-term fixed-rate debt      
Fair value of long-term fixed-rate debt 527,800 $ 529,000  
(Level 2) | Recurring basis      
Short-term investments:      
Short-term investments 15,716    
Assets:      
Total assets measured at fair value 15,716    
(Level 3) | Recurring basis      
Liabilities:      
Contingent earnout liability 17,356    
Corporate and municipal debt securities | Recurring basis      
Short-term investments:      
Short-term investments 15,716    
Corporate and municipal debt securities | (Level 2) | Recurring basis      
Short-term investments:      
Short-term investments 15,716    
U.S. government and federal agency securities | Recurring basis      
Short-term investments:      
Short-term investments 26,825    
U.S. government and federal agency securities | (Level 1) | Recurring basis      
Short-term investments:      
Short-term investments $ 26,825