Significant Accounting Policies Impairment (Details) - USD ($) $ in Thousands |
12 Months Ended | ||
---|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
|
Accounting Policies [Abstract] | |||
Impairment of Long-Lived Assets to be Disposed of | $ 111 | $ 137 | $ 0 |
Impairment of Intangible Assets, Indefinite-lived (Excluding Goodwill) | $ 0 | $ 0 | $ 0 |