Long-Term Liabilities (Schedule of Long-Term Liabilities) (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016	Dec. 31, 2015
Long-Term Liabilities [Abstract]
Indemnification liabilities - other (see Note 13)	$ 323	$ 357
Liabilities for uncertain tax positions	70,727	68,658	$ 71,285	$ 69,511
Other		244
Long term liabilities	$ 71,050	$ 69,259