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Summary of Significant Accounting Policies (Inventory) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($) compressor	Dec. 31, 2017 USD ($)
Accounting Policies [Abstract]
Inventory valuation reserves, deductions	$ 19	$ 15
Available-for-sale or rental, compressor units | compressor	7
Raw materials -current	$ 26,152	22,813
Raw materials - long term	3,980	2,829
Finished Goods	1,022	1,022
Work in process	3,800	2,389
Inventory	$ 34,954	$ 29,053

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Long Lived Assets Held-for-sale or Rental, Compressor Units

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Carrying amount, net of valuation reserves and adjustments, as of the balance sheet date of merchandise or goods held by the company that are readily available for sale.

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Carrying amount, net of reserves and adjustments, as of the balance sheet date of merchandise or goods which are partially completed. This inventory is generally comprised of raw materials, labor and factory overhead costs, which require further materials, labor and overhead to be converted into finished goods, and which generally require the use of estimates to determine percentage complete and pricing.

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