Segments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Interest expense	$ (1,112)	$ (9,751)	$ (21,579)
Depreciation and amortization	(8,363)	(7,439)	(7,908)
Restructuring and succession charges	(2,487)	(563)	(575)
Impairments related to variable interest entity	(5,674)	0	0
Foreign currency impact	(132)	117
Income from continuing operations before income taxes	7,620	15,914	9,689
Segment Reconciling Items
Segment Reporting Information [Line Items]
Interest expense	(1,112)	(9,751)	(21,579)
Depreciation and amortization	(34,875)	(28,643)	(30,316)
Acquisition and related costs	(21,978)	0	0
Restructuring and succession charges	(3,717)	(6,172)	(575)
Impairments related to variable interest entity	(7,043)	0	0
Equity compensation	4,512	(10,103)	(10,844)
COVID-19 benefits, net	0	4,123	0
Equity loss in unconsolidated investments	(1,868)	(467)	0
Foreign currency impact	(132)	117	(8)
Other items	(6,926)	(5,633)	(6,177)
U.S. | Operating Segments
Segment Reporting Information [Line Items]
Segment adjusted EBITDA	70,640	69,252	71,673
International | Operating Segments
Segment Reporting Information [Line Items]
Segment adjusted EBITDA	$ 10,119	$ 3,191	$ 7,515