Goodwill and Intangible Assets (Amortization) (Details) - USD ($)
$ in Thousands
Mar. 31, 2018
Dec. 31, 2017
Amortization of finite-lived intangible assets    
Remainder of 2018 $ 4,124  
2019 5,514  
2020 4,598  
2021 2,254  
2022 2,093  
Thereafter 6,044  
Intangible assets, net $ 24,627 $ 26,081