Income Taxes (Details 4) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Components of Deferred Tax Assets [Abstract]
Net operating loss and other credit carryforwards	$ 55,100	$ 38,835
Compensation and benefits	8,178	10,736
Inventories	213	280
Intangible assets	35,152	43,977
Pension plan	4,643	3,733
Allowance for doubtful accounts	1,552	1,860
Deferred revenue	4,619	7,622
Foreign tax credit and offset to branch deferreds	104,026	102,286
Other	41,318	17,786
less: valuation allowance	(104,509)	(102,769)
Net deferred tax assets	150,292	124,346
Components of Deferred Tax Liabilities [Abstract]
Intangible assets	(4,638)	(5,770)
Prepaid expenses	(142)	(163)
Property, plant and equipment	(219,247)	(178,505)
Equity Investment in partnerships	(85,385)	(78,813)
Other	(4,107)	(2,549)
Total deferred tax liabilities	(313,519)	(265,800)
Net deferred tax liabilities	$ (163,227)	$ (141,454)