CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash Flows from Operating Activities
Net income	$ 37,590	$ 54,988	$ 31,966
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	21,312	20,818	20,744
Amortization	4,490	3,995	3,334
Provision for doubtful accounts	482	280	18
Provision for warranties	16,725	18,912	13,743
Deferred compensation provision (benefit)	(574)	1,742	241
Deferred income tax benefit	(291)	(3,521)	(2,559)
Gain on disposition of fixed assets	(388)	(224)	(529)
Tax benefit from stock incentive plans	0	0	(345)
Stock-based compensation	3,142	2,936	1,250
Distributions to SERP participants	(206)	(532)	(2,986)
Change in operating assets and liabilities, net of effects of acquisitions:
Sale (purchase) of trading securities, net	473	(1,873)	(405)
Trade and other receivables	(7,749)	(4,895)	3,163
Inventories	(19,618)	30,839	(6,499)
Prepaid expenses	(5,181)	4,846	(3,016)
Other assets	(779)	2,069	(968)
Accounts payable	630	8,836	(11,409)
Customer deposits	9,379	(762)	(3,697)
Accrued product warranty	(14,642)	(15,125)	(14,177)
Income taxes payable	(597)	181	(4,093)
Accrued retirement benefit costs	45	(50)	24
Accrued loss reserves	122	229	103
Other accrued liabilities	(1,118)	11,142	3,576
Other	(1,366)	(25)	3,387
Net cash provided by operating activities	41,881	134,806	30,866
Cash Flows from Investing Activities
Business acquisition, net of cash acquired	(26,443)	(39,764)	178
Proceeds from sale of property and equipment	480	614	10,054
Expenditures for property and equipment	(20,046)	(27,367)	(21,202)
Sale (purchase) of investments	(891)	290	378
Net cash used by investing activities	(46,900)	(66,227)	(10,592)
Cash Flows from Financing Activities
Payment of dividends	(9,226)	(9,217)	(9,193)
Borrowings under bank loans	0	5,973	106,034
Repayment of bank loans	(7,242)	(5,903)	(104,567)
Proceeds from issuance of common stock	0	0	72
Tax benefit from stock option exercise	0	0	345
Purchase of shares of subsidiaries	(106)	(696)	(653)
Sale (purchase) of Company shares by SERP, net	289	(153)	2,084
Withholding tax paid upon vesting of restricted stock units	(507)	(1,024)	(600)
Proceeds from cash surrender value of life insurance	0	0	416
Net cash used by financing activities	(16,792)	(11,020)	(6,062)
Effect of exchange rates on cash	1,720	(250)	(2,173)
Increase (decrease) in cash and cash equivalents	(20,091)	57,309	12,039
Cash and cash equivalents, beginning of year	82,371	25,062	13,023
Cash and cash equivalents, end of year	62,280	82,371	25,062
Cash paid during the year for:
Interest	588	1,407	1,651
Income taxes, net of refunds	$ 26,917	$ 28,455	$ 29,573