Quarterly report pursuant to Section 13 or 15(d)

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

v3.3.0.814
Share-Based Payments Share-Based Payments - Employee Stock Purchase Plan (Details)
$ / shares in Units, $ in Thousands
9 Months Ended
Sep. 30, 2015
USD ($)
$ / shares
shares
Sep. 30, 2014
USD ($)
$ / shares
shares
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]    
Share-based compensation | $ $ 5,562 $ 5,005
Employee Stock Purchase Plan [Member]    
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]    
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized (in shares) | shares 398,705  
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  
Stock Issued During Period, Shares, Employee Stock Purchase Plans (in shares) | shares 5,087 3,814
Share-based Compensation Arrangement by Share-based Payment Award, Per Share Weighted Average Price of Shares Purchased (in dollars per share) $ 44.74 $ 38.88
Grants in Period, Weighted Average Grant Date Fair Value (in dollars per share) $ 7.52 $ 8.97
Share-based compensation | $ $ 37 $ 35