Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation (Narrative) (Details)

v3.10.0.1
Stock-Based Compensation (Narrative) (Details)
$ / shares in Units, shares in Thousands, $ in Thousands
3 Months Ended 9 Months Ended
Mar. 09, 2018
Sep. 30, 2018
USD ($)
$ / shares
shares
Sep. 30, 2017
USD ($)
Sep. 30, 2018
USD ($)
$ / shares
shares
Sep. 30, 2017
USD ($)
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]          
Stock-based compensation expense | $   $ 7,761 $ 4,369 $ 20,926 $ 10,968
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Dividend rate used       0.00%  
Weighted average GDFV of unvested shares (in dollars per share) | $ / shares   $ 46.77   $ 46.77  
Aggregate fair value of all restricted shares | $       $ 2,500  
Options          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Unrecognized compensation cost related to unvested options | $   $ 12,000   $ 12,000  
Weighted average period for compensation cost to be recognized       1 year 10 months 24 days  
RSAs          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Unrecognized compensation cost related to unvested restricted shares | $   $ 15,000   $ 15,000  
Weighted average period for compensation cost to be recognized       1 year 6 months  
Unvested restricted stock (in shares)   1,200   1,200  
RSUs          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Unvested restricted stock (in shares)   32   32  
Liberty Ventures          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Shares redemption ratio 1        
Series A common stock          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Options to purchase shares granted (in shares)       5  
Shares reserved for issuance upon exercise   1,600   1,600  
Series A common stock | Liberty Ventures          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Shares redemption ratio 1        
Series B common stock          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Options to purchase shares granted (in shares)       143  
Shares reserved for issuance upon exercise   1,200   1,200  
Series B common stock | Liberty Ventures          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Shares redemption ratio 1        
Directors | Series B common stock          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Options to purchase shares granted (in shares)       5  
Granted options, weighted average GDFV (in dollars per share) | $ / shares       $ 13.36  
CEO | Series B common stock          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Options to purchase shares granted (in shares)       143  
Granted options, weighted average GDFV (in dollars per share) | $ / shares       $ 16.55