Quarterly report pursuant to Section 13 or 15(d)

Share-Based Payments - Employee Stock Purchase Plan (Details)

v3.19.2
Share-Based Payments - Employee Stock Purchase Plan (Details)
shares in Thousands, $ / shares in Thousands, $ in Thousands
6 Months Ended
Jun. 30, 2019
USD ($)
$ / shares
shares
Jun. 30, 2018
USD ($)
$ / shares
shares
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]    
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized (in shares) | shares 357  
Share-based Compensation Arrangement by Share-based Payment Award, Discount from Market Price, Purchase Date 90.00%  
Number of Large Lump Sum Contributions Related to ESPP Stock Purchases 2  
Share-based compensation expense | $ $ 6,244 $ 4,678
Employee Stock Purchase Plan [Member]    
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]    
Stock Issued During Period, Shares, Employee Stock Purchase Plans (in shares) | shares 5 5
Share-based Compensation Arrangement by Share-based Payment Award, Per Share Weighted Average Price of Shares Purchased (in dollars per share) | $ / shares $ 49 $ 52
Grants in Period, Weighted Average Grant Date Fair Value (in dollars per share) | $ / shares $ 10 $ 7
Share-based compensation expense | $ $ 52 $ 32