Basis of Presentation (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2020 USD ($) segment	Mar. 31, 2019 USD ($)	Dec. 31, 2019 USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of reportable segments | segment	1
SUPPLEMENTAL CASH FLOW INFORMATION:
Interest paid	$ 712	$ 2,370
Income taxes paid, including foreign withholding taxes	2,228	3,196
Non-cash investing and financing activities:
Dividend payable	10,762	11,195	$ 10,746
Increases in noncontrolling interests	0	2,500
Accrued capitalized patent costs and property and equipment	$ (1,288)	$ (1,056)