Income Taxes (Details) $ in Thousands, $ in Millions	3 Months Ended			12 Months Ended
	Mar. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2015 MXN ($)
Income Tax Disclosure [Abstract]
Tax Cuts and Jobs Act of 2017, Transition tax liability and income tax expense				$ 6,900
Repatriation of foreign earnings				7,000
Tax Cuts and Jobs Act of 2017, foreign tax credit		$ 5,500		5,500
Tax Cuts and Jobs Act of 2017, deferred income tax expense (benefit)				$ (17,400)
Tax Cuts and Jobs Act of 2017, net tax benefit recognized		$ 3,400
Provision for income taxes	$ 3,091		$ 1,119
Income tax benefit, release of U.S. tax reserves					$ 3,900
Foreign tax authority | Mexico Tax Authority
Income Tax Contingency [Line Items]
Income tax assessment					$ 3,300	$ 60