Quarterly report pursuant to Section 13 or 15(d)

Recent Accounting Pronouncements (Details)

v3.10.0.1
Recent Accounting Pronouncements (Details) - USD ($)
$ in Thousands
 6 Months Ended
Jun. 30, 2018
Jun. 30, 2018
Jan. 01, 2018
Dec. 31, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]        
Retained earnings $ 2,571,299 $ 2,571,299   $ 2,568,764
Other current assets 2,776 2,776   2,797
Deferred income tax liabilities 943,401 943,401   932,593
Deferred revenue and other current liabilities 9,224 9,224   $ 5,168
Deferred revenue        
Deferred revenue current 8,700 8,700 $ 4,500  
Deferred revenue noncurrent 2,300 2,300 2,300  
Deferred revenue $ 11,000 11,000 6,800  
Revenue recognized   $ 3,600    
Revenue recognized percentage 90.00%      
Practical expedient modified contract   true    
ASU 2014-09 | Adjustment        
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]        
Retained earnings     1,200  
Other current assets     300  
Deferred income tax liabilities     400  
Deferred revenue and other current liabilities     $ (1,300)  
Minimum        
Deferred revenue        
Revenue recognized period 1 year      
Maximum        
Deferred revenue        
Revenue recognized period 3 years