Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash flows from operating activities:
Net income	$ 69,715	$ 55,253	$ 43,248
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization including impairment loss	11,031	11,914	15,341
Provision for doubtful accounts	1,442	939	349
Noncash stock compensation	2,205	2,093	1,198
Gain on sale of license			(4,652)
Deferred tax benefit	(158)	(591)	(1,374)
Change in fair value of derivatives	(302)	(1,254)	682
Changes in:
Accounts receivable	(23,032)	(6,016)	(13,156)
Inventories	(29,341)	(28,518)	(909)
Other assets	484	727	(297)
Accounts payable and accrued expenses	25,592	5,696	18,690
Income taxes, net	5,405	(4,352)	(4,556)
Net cash provided by operating activities	63,041	35,891	54,564
Cash flows from investing activities:
Purchases of short-term investments	(10,030)	(31,874)	(57,289)
Proceeds from sale of short-term investments	8,859	66,981	42,604
Purchase of equipment and leasehold improvements	(3,956)	(3,023)	(4,777)
Payment for intangible assets acquired	(8,509)	(1,046)	(965)
Proceeds from sale of trademark		5,886
Net cash provided by (used in) investing activities	(13,636)	36,924	(20,427)
Cash flows from financing activities:
Repayment of long-term debt	(23,487)	(22,362)	(21,884)
Purchase of treasury stock			(77)
Proceeds from exercise of options	3,406	1,963	1,579
Proceeds from sale of stock of subsidiary			1,565
Dividends paid	(26,287)	(21,192)	(18,015)
Dividends paid to noncontrolling interests	(8,706)	(6,039)	(4,863)
Purchase of subsidiary shares from noncontrolling interests	(808)		(2,941)
Net cash used in financing activities	(55,882)	(47,630)	(44,636)
Effect of exchange rate changes on cash	(8,730)	21,330	(4,640)
Net increase (decrease) in cash and cash equivalents	(15,207)	46,515	(15,139)
Cash and cash equivalents - beginning of year	208,343	161,828	176,967
Cash and cash equivalents - end of year	193,136	208,343	161,828
Cash paid for:
Interest	1,745	1,813	2,239
Income taxes	$ 24,995	$ 24,337	$ 28,124