Significant Accounting Policies Foreign Currency (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Component of Other Operating Cost [Line Items]
Other Nonoperating Income (Expense)	$ (342)	$ 3,669	$ 1,069
Foreign Currency Gain (Loss) [Member]
Component of Other Operating Cost [Line Items]
Other Nonoperating Income (Expense)	$ 1,832	$ 4,507	$ 4,230