Property, Plant and Equipment, Net (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, Net
Total property, plant, and equipment, gross	$ 290,327		$ 290,327		$ 280,391
Less: accumulated depreciation and amortization	(203,690)		(203,690)		(196,334)
Total property, plant, and equipment, net	86,637		86,637		84,057
Depreciation expense	7,000	$ 7,700	21,400	$ 22,800
Amortization of finance right-of-use assets	200	$ 100	500	$ 200
Land
Property, Plant and Equipment, Net
Total property, plant, and equipment, gross	554		554		634
Buildings
Property, Plant and Equipment, Net
Total property, plant, and equipment, gross	3,756		3,756		4,110
Furniture and fixtures
Property, Plant and Equipment, Net
Total property, plant, and equipment, gross	14,747		14,747		13,835
Machinery and equipment
Property, Plant and Equipment, Net
Total property, plant, and equipment, gross	25,826		25,826		25,438
Equipment leased to third parties under operating leases
Property, Plant and Equipment, Net
Total property, plant, and equipment, gross	27,510		27,510		29,217
Leasehold improvements
Property, Plant and Equipment, Net
Total property, plant, and equipment, gross	138,450		138,450		131,617
Computers and software
Property, Plant and Equipment, Net
Total property, plant, and equipment, gross	$ 79,484		$ 79,484		$ 75,540