Income Taxes Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands		Dec. 31, 2017		Dec. 30, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Deferred tax assets
Loss carryforwards		$ 218,420	[1]		$ 194,381
Tax Credit Carryforward, Amount		58,616	[2]		53,323
Accrued expenses		23,752			36,336
Pension plan benefits expense		18,262			16,822
Warranty reserves		11,170			21,306
Depreciation and amortization		5,736			15,698
Equity compensation		5,352			6,924
Inventory valuation		2,554			3,086
Deferred tax asset, deferred revenue		2,431			4,896
Other deferred tax assets, net		16,606			13,621
Total deferred tax assets		362,899			366,393
Valuation allowance		(285,784)			(249,560)	$ (235,339)	$ (257,728)
Total deferred tax assets, net of valuation allowance		77,115		$ 10,000	116,833
Deferred tax liabilities
Depreciation and amortization		(23,135)			(19,995)
Tax effect of accumulated translation		(303)			(100)
Other deferred tax liabilities, net		(5,231)			(5,698)
Total deferred tax liabilities		(28,669)			(25,793)
Net deferred tax assets		48,446			$ 91,040
Deferred Tax Assets, Tax Credit Carryforwards, General Business		3,700
Deferred Tax Assets, Tax Credit Carryforwards, Alternative Minimum Tax		3,300
Deferred Tax Assets, Tax Credit Carryforwards, Foreign		49,300
Deferred Tax Assets, Tax Credit Carryforwards, Other		10,700
U.S. federal
Deferred tax liabilities
Loss carryforwards by Jurisdiction	[1]	30,900
LUXEMBOURG
Deferred tax liabilities
Loss carryforwards by Jurisdiction	[1]	$ 592,600

[1] For tax return purposes at December 31, 2017, we had U.S. federal loss carryforwards of $30.9 million which begin to expire in the year 2021. At December 31, 2017, we have net operating loss carryforwards in Luxembourg of $592.6 million, majority of which can be carried forward indefinitely, offset by a full valuation allowance. The remaining portion of the loss carryforwards are composed primarily of losses in various other state and foreign jurisdictions. The majority of these losses can be carried forward indefinitely. At December 31, 2017, there was a valuation allowance of $285.8 million primarily associated with foreign loss carryforwards and foreign tax credit carryforwards (discussed below).

[2] For tax return purposes at December 31, 2017, we had: (1) U.S. general business credits of $3.7 million, which begin to expire in 2022; (2) U.S. alternative minimum tax credits of $3.3 million that can be carried forward indefinitely; (3) U.S. foreign tax credits of $49.3 million, which begin to expire in 2024; and (4) state tax credits of $10.7 million, which begin to expire in 2018.