Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 30, 2014	Mar. 31, 2013
Cash flows from operating activities:
Net income	$ 25,078	$ 26,801
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	7,066	5,810
Amortization	3,197	2,557
Stock-based compensation	5,139	4,364
Income taxes (receivable) payable, net	(2,898)	600
Deferred income taxes	1,455	976
(Increase) decrease, net of acquisitions, in:
Receivables	(10,760)	(9,284)
Inventories	(10,930)	(1,606)
Other assets	4,196	(512)
Increase (decrease), net of acquisitions, in:
Accounts payable	12,542	3,212
Accrued payroll liabilities	(13,725)	(9,645)
Accrued warranty reserves	545	421
Deferred revenue	1,152	10,587
Accrued restructuring, reorganization, relocation and severance	773	188
Other liabilities	5,619	341
Net cash provided by operating activities	28,449	34,810
Cash flows from investing activities:
Decrease (increase) in restricted cash	1,907	(3,462)
Acquisition of property, plant and equipment	(4,336)	(5,043)
Payments for acquisitions, net of cash acquired	(64,615)	0
Purchase of investments in marketable securities	(75,100)	(50,715)
Redemption of investments in marketable securities	49,374	34,030
Other	(268)	(293)
Net cash used in investing activities	(93,038)	(25,483)
Cash flows from financing activities:
Dividends paid on common stock	(5,058)	(3,078)
Withholding taxes paid on issuance of vested restricted stock units	(955)	(363)
Proceeds from exercise of stock options and employee stock purchases	5,504	4,146
Excess tax benefit for share based payment arrangements	1,866	586
Net cash provided by financing activities	1,357	1,291
Effect of exchange rate changes	(3,272)	(5,245)
(Decrease) increase in cash and cash equivalents	(66,504)	5,373
Cash and cash equivalents:
Beginning of period	384,170	266,302
End of period	317,666	271,675
Supplemental Cash Flow Information:
Cash paid for income taxes, net	3,711	2,656
Cash paid for interest	63	56
(Decrease) increase in fixed assets related to transfers with inventories	(240)	1,664
Dividends declared but not paid	5,056	3,078
Accrued purchases of plant and equipment	$ 8,345	$ 398