Impairment of Inventory and Long-Lived Assets for Discontinued Operations - Schedule of asset impairment charges (Details) - USD ($)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Segment Reporting Information [Line Items]
Property and equipment	$ 0	$ 0
Discontinued Operations, Held-for-sale
Segment Reporting Information [Line Items]
Total impairment		40,435,000
Discontinued Operations, Held-for-sale | Drilling Technologies
Segment Reporting Information [Line Items]
Inventories		12,653,000
Property and equipment		14,642,000
Intangible assets other than goodwill		9,227,000
Discontinued Operations, Held-for-sale | Production Technologies
Segment Reporting Information [Line Items]
Inventories		$ 3,913,000