Summary of Significant Accounting Policies - Foreign Currencies (Details 8) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Other Nonoperating Income (Expense) [Member]
Foreign Currencies
Foreign currency (loss) gain	$ (3,714)	$ (6,299)	$ (4,130)