Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Cash flows from operating activities:
Net loss	$ (41,358)	$ (10,895)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization	13,315	11,952
Asset impairments	3,872
Amortization of net premium (discount) on available-for-sale investments	(86)	(14)
Net gain on long-term investments	(8,195)	(5,400)
Net loss on disposal of property, plant and equipment	58	68
Gain on contingency	(1,230)
Gain on life insurance proceeds	(1,000)
Gain on bargain purchase of a business		(11,322)
Stock-based compensation expense	5,184	5,243
Deferred income taxes	30,421	(20,368)
Changes in operating assets and liabilities:
Accounts receivable, net	7,603	41,166
Other receivables	17,645	(1,842)
Inventory, net	(5,998)	16,543
Prepaid expenses and other assets	(10,071)	8,722
Accounts payable, net	(5,569)	5,223
Accrued expenses and other liabilities	10,564	156
Income tax payable	(5,073)	9,461
Net cash provided by operating activities	10,082	48,693
Cash flows from investing activities:
Purchases of property, plant and equipment	(6,008)	(5,695)
Proceeds from sales and maturities of debt and equity investments	38,561	116,757
Purchases of debt and equity investments	(37,223)	(115,271)
Life insurance proceeds received	1,000
Acquisition of business	13	(7,806)
Net cash used in investing activities	(3,657)	(12,015)
Cash flows from financing activities:
Proceeds from stock option exercises	526	1,321
Purchases of treasury stock	(184)	(14,185)
Dividend payments	(12,908)	(12,976)
Net cash used in financing activities	(12,566)	(25,840)
Net increase (decrease) in cash and cash equivalents	(6,141)	10,838
Effect of exchange rate changes	(2,956)	(3,098)
Cash and cash equivalents, beginning of period	105,504	86,433
Cash and cash equivalents, end of period	96,407	94,173
Supplemental disclosure of non-cash investing activities:
Purchases of property, plant and equipment included in accounts payable	$ 135	$ 355