Additional Balance Sheet Detail and Supplemental Cash Flow Information (Details 2) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Other Liabilities Disclosure [Abstract]
Other Accrued Liabilities	$ 12,323	$ 3,199
Accrued Income Taxes, Current	25,788	3,721
Accrual for Taxes Other than Income Taxes, Current	4,354	2,738
Interest Payable, Current	1,513	5,892
Accrued Salaries, Current	26,559	20,895
Business Combination, Contingent Consideration, Liability, Current	24,393	0
Accrued liabilities and other	$ 94,930	$ 36,445