Rental Equipment (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Property, Plant and Equipment [Line Items]
Accumulated depreciation	$ 165,200		$ 165,200		$ 156,928
Depreciation - Property, plant and equipment			10,546	$ 9,407
Rental Equipment
Property, Plant and Equipment [Line Items]
Accumulated depreciation	20,100		20,100		$ 18,000
Depreciation - Property, plant and equipment	$ 2,200	$ 2,600	$ 4,400	$ 5,200