Business Segments - (Net Sales by Product) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Revenue from External Customer [Line Items]
Revenues	$ 226,191	$ 224,200	$ 225,864	$ 196,202	$ 224,043	$ 211,906	$ 196,300	$ 218,440	$ 872,457	$ 850,689	$ 927,964
Europe
Revenue from External Customer [Line Items]
Revenues									499,118	468,041	533,048
North America
Revenue from External Customer [Line Items]
Revenues									340,980	348,307	348,201
All Other
Revenue from External Customer [Line Items]
Revenues									32,359	34,341	46,715
Operating Segments | Europe
Revenue from External Customer [Line Items]
Revenues									499,118	468,041	533,048
Operating Segments | Europe | Lifestyle Products
Revenue from External Customer [Line Items]
Revenues									248,325	222,668	245,987
Operating Segments | Europe | Mobility and Seating
Revenue from External Customer [Line Items]
Revenues									214,398	200,687	249,144
Operating Segments | Europe | Respiratory Therapy
Revenue from External Customer [Line Items]
Revenues									19,348	24,786	19,258
Operating Segments | Europe | Other Products and Services
Revenue from External Customer [Line Items]
Revenues									17,047	19,900	18,659
Operating Segments | North America
Revenue from External Customer [Line Items]
Revenues									340,980	348,307	348,201
Operating Segments | North America | Lifestyle Products
Revenue from External Customer [Line Items]
Revenues									148,369	165,267	173,039
Operating Segments | North America | Mobility and Seating
Revenue from External Customer [Line Items]
Revenues									110,998	109,923	121,955
Operating Segments | North America | Respiratory Therapy
Revenue from External Customer [Line Items]
Revenues									80,903	72,285	51,649
Operating Segments | North America | Other Products and Services
Revenue from External Customer [Line Items]
Revenues									710	832	1,558
Operating Segments | All Other
Revenue from External Customer [Line Items]
Revenues									32,359	34,341	46,715
Operating Segments | All Other | Lifestyle Products
Revenue from External Customer [Line Items]
Revenues									11,438	13,503	10,831
Operating Segments | All Other | Mobility and Seating
Revenue from External Customer [Line Items]
Revenues									12,112	14,150	28,448
Operating Segments | All Other | Respiratory Therapy
Revenue from External Customer [Line Items]
Revenues									3,101	1,383	1,283
Operating Segments | All Other | Other Products and Services
Revenue from External Customer [Line Items]
Revenues									$ 5,708	$ 5,305	$ 6,153