Rental Equipment (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Accumulated depreciation	$ 152,276		$ 152,276		$ 141,388
Depreciation - Property, plant and equipment			14,237	$ 10,583
Rental Equipment
Property, Plant and Equipment [Line Items]
Accumulated depreciation	16,900		16,900		$ 14,600
Depreciation - Property, plant and equipment	$ 2,300	$ 2,400	$ 7,500	$ 6,800