Income Taxes (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Tax Credit Carryforward [Line Items]
Valuation allowance	$ 30,953	$ 20,659
Unrecognized tax benefits affecting effective tax rate	39,900
Interest and penalties associated with unrecognized tax benefits (Operations)	(500)
Interest and penalties associated with unrecognized tax benefits (Balance Sheet)	28,100
State and Local Jurisdiction
Tax Credit Carryforward [Line Items]
Net operating loss carryforwards	316,600
Deferred tax assets, operating loss and tax credit carryforwards	24,600
State and Local Jurisdiction | Wisconsin
Tax Credit Carryforward [Line Items]
Valuation allowance	4,600
State and Local Jurisdiction | Wisconsin Research And Development Credit | Wisconsin
Tax Credit Carryforward [Line Items]
Net capital loss carryforwards	12,700
Foreign Tax Authority
Tax Credit Carryforward [Line Items]
Net operating loss carryforwards	9,000
Deferred tax assets, operating loss and tax credit carryforwards	17,300
Operating loss carryforwards, valuation allowance	26,300
Operating loss carryforward, increase in valuation allowance	$ 5,700