Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 29, 2019	Jun. 30, 2018
Statement of Cash Flows [Abstract]
Cash and cash equivalents at beginning of period	$ 533,298	$ 688,087
Cash flows from operating activities:
Net income	227,790	148,034
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	61,197	59,282
Amortization of debt discount and fees	497	586
Stock-based compensation	86,510	78,857
(Gain) loss on investments, net	259	(1,541)
Deferred income taxes	(8,159)	1,664
Provisions for losses on receivables	(386)	1,015
ROU asset amortization and change in operating lease liabilities	2,504	0
Other non-cash items	160	(133)
Changes in operating assets and liabilities, net of effect of acquired businesses:
Receivables	63,876	(2,606)
Inventories	(25,689)	1,932
Prepaid expenses and other	33,055	13,294
Other assets	2,547	5,027
Accounts payable and accrued liabilities	(34,670)	(11,832)
Deferred revenue	19,707	71,667
Other long-term liabilities	2,576	(2,333)
Net cash provided by operating activities	431,774	362,913
Cash flows from investing activities:
Purchases of non-marketable investments	(33,717)	0
Proceeds from the sale of non-marketable investments	2,952	0
Purchases of property, plant and equipment	(30,562)	(31,105)
Payments to Acquire Businesses, Net of Cash Acquired	(338)	0
Net cash used for investing activities	(61,665)	(31,105)
Cash flows from financing activities:
Proceeds from revolving credit facility	150,000	0
Payment on revolving credit facility	(250,000)	(85,000)
Proceeds from issuance of common stock	32,855	25,656
Stock received for payment of employee taxes on vesting of restricted stock	(45,698)	(30,125)
Payments for repurchases of common stock	(156,120)	(100,025)
Change in book overdraft	0	(3,867)
Net cash used for financing activities	(268,963)	(193,361)
Effect of exchange rate changes on cash and cash equivalents	(1,029)	(6,994)
Increase in cash and cash equivalents	100,117	131,453
Cash and cash equivalents at end of period	633,415	819,540
Supplemental cash flow information:
Cash paid for interest	10,052	13,165
Cash paid for taxes, net	$ 17,708	$ 17,807