Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Cash flows from operating activities:
Net loss	$ (3,736)	$ (41,358)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization	12,525	13,315
Asset impairments	65	3,872
Amortization of net premium on available-for-sale investments	90	(86)
Net gain on long-term investments	(1,819)	(8,195)
Net loss on disposal of property, plant and equipment	105	58
Gain on contingency		(1,230)
Gain on life insurance proceeds		(1,000)
Stock-based compensation expense	5,056	5,184
Deferred income taxes	(1)	30,421
Changes in operating assets and liabilities:
Accounts receivable, net	(9,131)	7,603
Other receivables	(6,224)	17,645
Inventory	(21,170)	(5,998)
Prepaid expenses and other assets	(672)	(10,071)
Accounts payable, net	14,204	(5,569)
Accrued expenses and other liabilities	5,618	10,564
Income taxes payable	(227)	(5,073)
Net cash provided by (used in) operating activities	(5,317)	10,082
Cash flows from investing activities:
Purchases of property, plant and equipment	(5,082)	(6,008)
Proceeds from sales and maturities of available-for-sale investments	86,145	38,561
Purchases of available-for-sale investments	(42,641)	(37,223)
Acquisition of note receivable	(523)
Life insurance proceeds received		1,000
Acquisition of business		13
Net cash provided by (used in) investing activities	37,899	(3,657)
Cash flows from financing activities:
Dividend payments	(12,993)	(12,908)
Repayment of bonds payable	(24,600)
Proceeds from stock option exercises		526
Purchases of treasury stock		(184)
Net cash used in financing activities	(37,593)	(12,566)
Net decrease in cash, cash equivalents and restricted cash	(5,011)	(6,141)
Effect of exchange rate changes	2,641	(2,956)
Cash, cash equivalents and restricted cash, beginning of period	73,773	105,504
Cash, cash equivalents and restricted cash, end of period	71,403	96,407
Supplemental disclosure of non-cash investing activities:
Purchases of property, plant and equipment included in accounts payable	$ 442	$ 135