Other Liabilities (Schedule of Other Liabilities) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2016
Other Liabilities [Abstract]
Indemnification liabilities - other (see Note 13)	$ 190	$ 293
Liabilities for uncertain tax positions	63,200	61,182	$ 70,727	$ 68,658
Other liabilities	$ 63,390	$ 61,475