Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Valuation Allowance [Line Items]
Deferred Tax Assets, Gross	$ 183,600		$ 183,600
Deferred Tax Assets, Valuation Allowance	196,500		196,500
Deferred Tax Liabilities, Net	12,800		12,800
Provision for (benefit from) income taxes	(1,312)	$ 89,758	3,369	$ 85,514
Unrecognized tax benefits	24,300		24,300		$ 23,500
Portion of unrecognized tax benefits, which if recognized, would be recorded as an income tax benefit	2,100		2,100
Foreign Tax Authority [Member]
Valuation Allowance [Line Items]
Income Taxes Paid	4,300	$ 5,100	13,000	$ 16,200
Long Term Deferred Tax Assets [Member]
Valuation Allowance [Line Items]
Unrecognized tax benefits	22,200		22,200		21,400
Long Term Income Taxes Payable [Member]
Valuation Allowance [Line Items]
Unrecognized tax benefits	$ 2,100		$ 2,100		$ 2,100