Property, Plant and Equipment, Net - Property, Plant and Equipment, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Property, Plant and Equipment, Net
Total property, plant, and equipment, gross	$ 314,037	$ 304,585
Less: accumulated depreciation and amortization	(231,603)	(219,712)
Total property, plant, and equipment, net	82,434	84,873
Land
Property, Plant and Equipment, Net
Total property, plant, and equipment, gross	454	454
Buildings
Property, Plant and Equipment, Net
Total property, plant, and equipment, gross	3,031	3,044
Furniture and fixtures
Property, Plant and Equipment, Net
Total property, plant, and equipment, gross	14,737	15,079
Machinery and equipment
Property, Plant and Equipment, Net
Total property, plant, and equipment, gross	27,429	25,759
Equipment leased to third parties under operating leases
Property, Plant and Equipment, Net
Total property, plant, and equipment, gross	35,408	40,137
Less: accumulated depreciation and amortization	(22,826)	(25,430)
Total property, plant, and equipment, net	12,582	14,707
Leasehold improvements
Property, Plant and Equipment, Net
Total property, plant, and equipment, gross	149,337	139,322
Computers and software
Property, Plant and Equipment, Net
Total property, plant, and equipment, gross	$ 83,641	$ 80,790