Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Operating activities:
Net income	$ 74,526	$ 68,825	$ 124,246
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	29,468	28,013	26,839
Amortization	9,347	9,594	10,225
Share-based compensation expense	7,928	9,881	7,519
Deferred tax valuation allowance	445	358	(41,038)
Provision for deferred income taxes	7,787	11,582	21,671
Charge for excess and obsolete inventory	3,963	4,007	3,167
Excess tax benefit from share-based compensation plans	(3,914)	(3,805)	(657)
Amortization of debt issuance costs	0	0	676
Net income attributable to noncontrolling interest	0	0	(400)
Other	(765)	1,701	(2,245)
Changes in operating assets and liabilities, net of effects of acquisitions:
Trade accounts receivable and notes receivable	(13,363)	10,626	19,336
Inventories	(441)	(6,118)	3,632
Accounts payable and accrued liabilities	(4,408)	6,265	(15,127)
Other current assets	(414)	(2,985)	1,253
Income taxes payable and refundable income taxes	2,731	(11,015)	(433)
Other	(3,488)	(11,767)	(1,378)
Net cash provided by operating activities	109,402	115,162	157,286
Investing activities:
Acquisition of property and equipment	(60,360)	(49,929)	(30,267)
Acquisition of business, net of cash acquired	(13,358)	(2,961)	0
Purchase of short-term investments	0	(27,990)	(2,047)
Proceeds from sale or maturities of short-term investments	20,000	8,000	2,000
Proceeds from sale of assets held for sale	6,500	0	0
Other	189	413	1,883
Net cash used in investing activities	(47,029)	(72,467)	(28,431)
Financing activities:
Issuance of common stock from employee stock plans	7,685	7,431	11,690
Repurchase and retirement of common stock	(15,494)	(427)	0
Other	3,914	3,886	(826)
Net cash (used in) provided by financing activities	(3,895)	10,890	10,864
Effect of exchange rate changes on cash and cash equivalents	(4,471)	3,241	(80)
Increase in cash and cash equivalents	54,007	56,826	139,639
Cash and cash equivalents at beginning of year	330,419	273,593	133,954
Cash and cash equivalents at end of year	384,426	330,419	273,593
Supplemental Cash Flow Information
Equipment purchases in accounts payable	6,950	3,429	1,372
Intangible assets received as partial consideration in sale of equity interest	0	0	1,712
Schedule of interest and income taxes paid:
Interest paid	72	271	210
Income taxes, net of refunds received	$ 10,208	$ 29,697	$ 22,034