Income Taxes (Details 4) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Components of Deferred Tax Assets [Abstract]
Net operating loss and other credit carryforwards	$ 58,129	$ 55,100
Compensation and benefits	9,411	8,178
Inventories	231	213
Intangible assets	34,573	35,152
Pension plan	4,811	4,643
Allowance for doubtful accounts	971	1,552
Deferred revenue	4,451	4,619
Deferred Tax Assets, Equity Method Investments	54,686	0
Foreign tax credit and offset to branch deferreds	110,052	104,026
Other	46,601	41,318
less: valuation allowance	(110,243)	(104,509)
Deferred Tax Assets, Net of Valuation Allowance	213,673	150,292
Components of Deferred Tax Liabilities [Abstract]
Intangible assets	(4,709)	(4,638)
Prepaid expenses	(136)	(142)
Property, plant and equipment	(223,325)	(219,247)
Equity Investment in partnerships	0	(85,385)
Other	(4,411)	(4,107)
Total deferred tax liabilities	(232,581)	(313,519)
Net deferred tax liabilities	$ (18,908)	$ (163,227)