Fair Value (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Level 1 [Member]
Investments, Fair Value Disclosure [Abstract]
Investments	$ 100	$ 100
Level 2 [Member]
Investments, Fair Value Disclosure [Abstract]
Forward exchange contracts, liability		$ 600
Level 2 [Member] | Carrying Value [Member]
Investments, Fair Value Disclosure [Abstract]
Long term debt	732,800
Level 2 [Member] | Fair Value [Member]
Investments, Fair Value Disclosure [Abstract]
Long term debt	$ 740,700