Income Taxes (Components of deferred tax assets and liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Components of Deferred Tax Assets and Liabilities [Abstract]
Net operating loss carryforwards	$ 25,905	$ 13,207
Income tax credits	98,158	107,532
Property, plant and equipment	27,199	38,050
Deferred interest expense	12,361	5,415
Accrued liabilities	61,812	68,402
Receivable	30,558	31,729
Unrealized foreign exchange loss	2,750	1,410
Operating lease liabilities	18,164
Other	11,889	14,545
Total deferred tax assets	288,796	280,290
Valuation allowance	(136,934)	(118,560)
Total deferred tax assets net of valuation allowance	151,862	161,730
Property, plant and equipment	23,747	14,605
Deferred gain	11,193	11,651
Unrealized foreign exchange gain	1,195	1,695
Unbilled receivables	3,580	9,515
Operating lease right of use assets	17,687
Other	4,125	5,805
Total deferred tax liabilities	61,527	43,271
Other assets	90,465	118,697
Other non-current liabilities	(130)	(238)
Net deferred tax assets	$ 90,335	$ 118,459