Income Taxes (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating Loss Carryforwards [Line Items]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	35.00%	35.00%	35.00%
Change in valuation allowance	$ (64,600)
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Percent	21.00%
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount	$ 17,638	$ 0	$ 0
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Share-based Compensation Cost, Amount	1,351	$ 0	$ 0
Effective Income Tax Rate Reconciliation, Tax Credit, Foreign, Amount	27,600
Domestic Tax Authority [Member]
Operating Loss Carryforwards [Line Items]
Federal net operating loss	165,500
State and Local Jurisdiction [Member]
Operating Loss Carryforwards [Line Items]
Federal net operating loss	148,700
Foreign Tax Authority [Member]
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Operating Loss Carryforwards, Subject to Expiration	20,900
Deferred Tax Assets, Operating Loss Carryforwards, Subject to Expiration	400
Forgein income tax credits	44,600
Foreign tax credits and offset to branch deferreds [Member]
Operating Loss Carryforwards [Line Items]
Change in valuation allowance	(65,400)
Foreign Net Operating Losses [Domain]
Operating Loss Carryforwards [Line Items]
Change in valuation allowance	100
State Net Operating Losses [Member]
Operating Loss Carryforwards [Line Items]
Change in valuation allowance	$ 700