CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 340,020	$ 286,219	$ 212,029
Adjustments to reconcile net income to net cash provided by operating activities:
Amortization of trademark	49	52	48
Depreciation and amortization	20,513	17,032	11,728
Loss (gain) on disposal of property and equipment	25	(18)	194
Stock-based compensation	28,413	19,424	16,862
Loss (gain) on put option	1,111	727	(3,768)
(Gain) loss on investments, net	(1,897)	43	4,526
Deferred income taxes	(2,460)	(687)	(1,361)
Tax benefit from exercise of stock options	(19,656)	(3,824)	(12,374)
Provision for doubtful accounts	(10)	52	1,659
Effect on cash of changes in operating assets and liabilities:
Accounts receivable	(17,772)	(56,752)	(12,669)
Distributor receivables	3	(256)	4,286
Inventories	(47,568)	(4,465)	(44,973)
Prepaid expenses and other current assets	(4,523)	(6,209)	(2,774)
Prepaid income taxes	(33,210)	9,470	(9,992)
Accounts payable	3,659	26,250	33,352
Accrued liabilities	6,458	8,144	13,174
Accrued promotional allowances	2,723	28,442	14,702
Accrued distributor terminations	794	(330)	(2,570)
Accrued compensation	2,498	2,878	(66)
Income taxes payable	14,165	13,918	12,505
Deferred revenue	(5,659)	(6,283)	(5,474)
Net cash provided by operating activities	287,676	333,827	229,044
CASH FLOWS FROM INVESTING ACTIVITIES:
Maturities of held-to-maturity investments	841,576	407,918	107,992
Sales of available-for-sale investments	68,451	30,545	13,201
Sales of trading investments	17,050	34,715	7,400
Purchases of held-to-maturity investments	(597,155)	(583,138)	(257,474)
Purchases of available-for-sale investments	(9,502)	(33,312)	(59,907)
Purchases of property and equipment	(42,935)	(25,552)	(12,545)
Proceeds from sale of property and equipment	288	519	115
Additions to Intangibles	(6,301)	(5,132)	(9,852)
Decrease (increase) in other assets	377	410	(1,440)
Net cash provided by (used in) investing activities	271,849	(173,027)	(212,510)
CASH FLOWS FROM FINANCING ACTIVITIES:
Principal payments on debt	(2,076)	(1,942)	(420)
Tax benefit from exercise of stock options	19,656	3,824	12,374
Issuance of common stock	11,015	20,318	20,824
Purchases of common stock held in treasury	(727,670)	(176,392)	(23,540)
Net cash (used in) provided by financing activities	(699,075)	(154,192)	9,238
Effect of exchange rate changes on cash and cash equivalents	2,733	(2,119)	721
NET (DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS	(136,817)	4,489	26,493
CASH AND CASH EQUIVALENTS, beginning of year	359,331	354,842	328,349
CASH AND CASH EQUIVALENTS, end of year	222,514	359,331	354,842
Cash paid during the year for:
Interest	48	48	13
Income taxes	$ 230,221	$ 147,927	$ 136,369