Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Valuation Allowance [Line Items]
Deferred Tax Assets, Gross	$ 165,600
Deferred Tax Assets, Valuation Allowance	179,900
Deferred Tax Liabilities, Net	14,300
Provision for (benefit from) income taxes	309	$ (3,229)
Unrecognized tax benefits	24,500		$ 23,500
Portion of unrecognized tax benefits, which if recognized, would be recorded as an income tax benefit	2,300
Foreign Tax Authority [Member]
Valuation Allowance [Line Items]
Income Taxes Paid	4,300	$ 6,100
Long Term Deferred Tax Assets [Member]
Valuation Allowance [Line Items]
Unrecognized tax benefits	22,200		21,400
Long Term Income Taxes Payable [Member]
Valuation Allowance [Line Items]
Unrecognized tax benefits	$ 2,300		$ 2,100