Income Taxes - Summary of deferred tax assets related to loss carryforwards and tax credits (Parentheticals) (Details 4) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Israel
Deferred Tax Assets Related To Loss Carryforwards And Tax Credits [Line Items]
Net operating loss carry forwards related to subsidiary, expiration period	10 years
Mexico
Deferred Tax Assets Related To Loss Carryforwards And Tax Credits [Line Items]
Net operating loss carry forwards related to subsidiary, expiration period	10 years
Mexico and Israel
Deferred Tax Assets Related To Loss Carryforwards And Tax Credits [Line Items]
Operating loss carryforward gross tax effect	$ 2.9
U.S.
Deferred Tax Assets Related To Loss Carryforwards And Tax Credits [Line Items]
Operating loss carryforward gross tax effect	$ 33.9	$ 130.5
Foreign
Deferred Tax Assets Related To Loss Carryforwards And Tax Credits [Line Items]
Net operating loss carry forwards related to subsidiary, expiration period	16 years