Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands		Dec. 31, 2019		Dec. 31, 2018
Deferred tax assets
Loss carryforwards		$ 343,614	[1]	$ 370,120
Tax credits		98,098	[2]	94,359
Accrued expenses		46,846		43,213
Pension plan benefits expense		17,310		18,086
Warranty reserves		12,961		13,470
Depreciation and amortization		6,112		5,709
Equity compensation		4,685		5,390
Inventory valuation		1,069		1,415
Deferred revenue		8,951		9,062
Leases		13,876		0
Other deferred tax assets, net		9,777		11,319
Total deferred tax assets		563,299		572,143
Valuation allowance		(320,649)	[1]	(323,822)
Total deferred tax assets, net of valuation allowance		242,650		248,321
Deferred tax liabilities
Depreciation and amortization		(161,044)		(178,358)
Leases		(12,976)		0
Other deferred tax liabilities, net		(6,540)		(6,676)
Total deferred tax liabilities		(180,560)		(185,034)
Net deferred tax assets		62,090		$ 63,287
Deferred tax assets, tax credit carryforwards, general business	[2]	39,000
Deferred tax assets, tax credit carryforwards, alternative minimum tax	[2]	800
Deferred tax assets, tax credit carryforwards, foreign	[2]	50,500
Deferred tax assets, tax credit carryforwards, other	[2]	34,400
U.S. federal
Deferred tax liabilities
Loss carryforwards by Jurisdiction	[1]	187,500
LUXEMBOURG
Deferred tax liabilities
Loss carryforwards by Jurisdiction	[1]	$ 992,700

[1] For tax return purposes at December 31, 2019, we had U.S. federal loss carryforwards of $187.5 million, which begin to expire in the year 2020. At December 31, 2019, we have net operating loss carryforwards in Luxembourg of $992.7 million, the 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, 2019, there was a valuation allowance of $320.6 million primarily associated with foreign loss carryforwards and foreign tax credit carryforwards (discussed below).

[2] For tax return purposes at December 31, 2019, we had: (1) U.S. general business credits of $39.0 million, which begin to expire in 2022; (2) U.S. alternative minimum tax credits of $0.8 million that can be carried forward indefinitely; (3) U.S. foreign tax credits of $50.5 million, which begin to expire in 2024; and (4) state tax credits of $34.4 million, which begin to expire in 2020.