Condensed Consolidated Statements of Cash Flows (unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Cash flows from operating activities:
Net income	$ 15,080	$ 17,678
Adjustments to reconcile net income to net cash provided (used) by operating activities:
Depreciation and amortization	6,411	5,870
Provision for doubtful accounts	436	289
Provision for warranties	3,996	3,615
Deferred compensation provision (benefit)	(376)	380
Stock-based compensation	1,017	511
Gain on disposition of fixed assets	(133)	(71)
Distributions to SERP participants	(123)	(92)
Change in operating assets and liabilities:
Sale (purchase) of trading securities, net	406	(678)
Trade and other receivables	(45,910)	(17,667)
Inventories	(12,166)	(4,728)
Prepaid expenses	778	(4,042)
Other assets	(377)	1,384
Accounts payable	16,276	8,193
Accrued payroll and related expenses	(7,687)	(975)
Accrued product warranty	(3,460)	(2,357)
Customer deposits	(154)	22,138
Prepaid and income taxes payable, net	7,877	9,745
Other	3,387	5,870
Net cash provided (used) by operating activities	(14,722)	45,063
Cash flows from investing activities:
Expenditures for property and equipment	(5,406)	(5,054)
Proceeds from sale of property and equipment	140	111
Other	(292)	(12)
Net cash used by investing activities	(5,558)	(4,955)
Cash flows from financing activities:
Payment of dividends	(2,306)	(2,304)
Borrowings under bank loans	0	1,394
Repayments of bank loans	(4,601)	(1,120)
Sale (purchase) of Company shares by SERP, net	285	(20)
Withholding tax paid upon vesting of restricted stock units	(501)	(1,022)
Net cash used by financing activities	(7,123)	(3,072)
Effect of exchange rates on cash	433	347
Net increase (decrease) in cash and cash equivalents	(26,970)	37,383
Cash and cash equivalents, beginning of period	82,371	25,062
Cash and cash equivalents, end of period	$ 55,401	$ 62,445