Annual report pursuant to Section 13 and 15(d)

Share-Based Compensation (Schedule of Unrecognized Compensation Cost) (Details)

v3.8.0.1
Share-Based Compensation (Schedule of Unrecognized Compensation Cost) (Details) - USD ($)
$ in Thousands
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
RSU equity awards      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Unrecognized compensation cost related to unvested awards $ 13,158 $ 7,276 $ 5,208
Cash-settleable RSU awards      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Unrecognized compensation cost related to unvested awards $ 3,776 $ 8,948 $ 4,728