Income Taxes Operating Loss Carryforwards (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating loss carryforwards [Abstract]
Employee Service Share-based Compensation, Tax Benefit from Exercise of Stock Options	$ 12,617	$ 20,004	$ 7,556
UNITED STATES | Tax Year 2017 [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	68,900
Foreign Tax Authority [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	21,400
State and Local Jurisdiction [Member] | Tax Year 2018 [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	$ 20,200