Impairment of Inventory and Long-Lived Assets for Discontinued Operations (Details) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2016	Jun. 30, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Property and equipment			$ 0	$ 0	$ 0
Impairment of inventory and rental equipment	$ 40,435,000	$ 20,372,000
Drilling Technologies:
Segment Reporting Information [Line Items]
Inventories	12,653,000	17,241,000
Property and equipment	14,642,000	2,327,000
Intangible assets other than goodwill	9,227,000	0
Production Technologies:
Segment Reporting Information [Line Items]
Inventories	$ 3,913,000	$ 804,000