Condensed Consolidated Statements of Cash Flows (unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Cash flows from operating activities:
Net income	$ 13,251	$ 12,258
Adjustments to reconcile net income to net cash provided (used) by operating activities:
Depreciation and amortization	5,428	5,901
Provision for doubtful accounts	388	8
Provision for warranties	2,760	2,742
Deferred compensation benefit	186	446
Sale of trading securities, net	109	128
Stock-based compensation	435	61
Tax expense (benefit) from stock incentive plans	76	(173)
Deferred income tax provision (benefit)	(249)	2,895
Gain on disposition of fixed assets	(65)	(141)
(Increase) decrease in:
Trade and other receivables	(15,788)	(11,351)
Inventories	(13,385)	(18,239)
Prepaid expenses	(5,784)	2,550
Other assets	(1,070)	(764)
Increase (decrease) in:
Accounts payable	4,571	967
Accrued product warranty	(2,482)	(3,210)
Customer deposits	10,255	(4,723)
Prepaid and income taxes payable	5,638	2,499
Other current liabilities	(3,488)	(3,368)
Net cash provided (used) by operating activities	786	(11,514)
Cash flows from investing activities:
Expenditures for property and equipment	(9,339)	(5,369)
Proceeds from sale of property and equipment	77	463
Net cash used by investing activities	(9,262)	(4,906)
Cash flows from financing activities:
Tax (expense) benefit from stock option exercise	(76)	173
Supplemental Executive Retirement Plan transactions, net	60	(58)
Withholding tax paid upon vesting of restricted stock units	(783)	(686)
Proceeds from exercise of stock options	36	493
Sale of subsidiaries shares to minority shareholders	1,673	0
Net cash provided (used) by financing activities	910	(78)
Effect of exchange rates on cash	(188)	635
Net decrease in cash and cash equivalents	(7,754)	(15,863)
Cash and cash equivalents, beginning of period	80,929	57,505
Cash and cash equivalents, end of period	$ 73,175	$ 41,642