Segment Information Foreign Currency Exchange Rates (Details)	Mar. 31, 2018 $ / £	Mar. 31, 2018 $ / $	Mar. 31, 2018 $ / $	Mar. 31, 2018 $ / €	Dec. 31, 2017 $ / £	Dec. 31, 2017 $ / $	Dec. 31, 2017 $ / $	Dec. 31, 2017 $ / €	May 03, 2017 $ / £	Mar. 31, 2017 $ / £	Mar. 31, 2017 $ / $	Mar. 31, 2017 $ / $	Mar. 31, 2017 $ / €
Foreign currency exchange rate									1.29
Last day rate [Member] [Member]
Foreign currency exchange rate	1.40	0.77	0.78	1.23	1.35	0.78	0.80	1.20
Quarter to Date Average [Member]
Foreign currency exchange rate	1.39	0.79	0.79	1.23						1.24	0.76	0.76	1.07