Intangible Assets, Goodwill and Other (Tables)

12 Months Ended

Dec. 31, 2020

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule Of Identifiable Intangible Assets [Table Text Block]

	December 31,
(in thousands)	2020		2019
Intangible assets subject to amortization:
Patents and purchased technology	$	14,198	$	14,198
Customer relationships	23,000		23,000
Gross carrying amount	37,198		37,198
Accumulated amortization:
Patents and purchased technology	(14,198)		(13,311)
Customer relationships	(17,363)		(15,713)
Accumulated amortization	(31,561)		(29,024)
Net carrying amount	5,637		8,174
Intangible assets not subject to amortization	97,921		115,421
Intangible assets, net	$	103,558	$	123,595

Schedule of Finite-Lived Intangible Assets, Future Amortization Expense

The following table presents the estimated annual amortization expense for the years 2021 through 2025:

(in thousands)
2021	$	1,650
2022	1,650
2023	1,650
2024	688
2025	—