Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 72,643	$ 63,857
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization expense	12,549	12,335
Amortization of debt costs	629	582
Increase in provision for inventory losses	3,993	2,797
Increase in receivables	(9,418)	(10,455)
Increase in inventory	(23,058)	(55,884)
Increase in prepaids and other current assets	(5,049)	(1,614)
Increase in accounts payable	13,256	37,473
Increase in deferred revenue and other current liabilities	27,599	19,221
Other operating activities	2,383	2,404
Net cash provided by operating activities	95,527	70,716
CASH FLOWS FROM INVESTING ACTIVITIES:
Capital expenditures	(9,917)	(9,220)
Other investing activities	(682)	(1,388)
Net cash used in investing activities	(10,599)	(10,608)
CASH FLOWS FROM FINANCING ACTIVITIES:
Dividends paid to shareholders	(14,728)	(11,497)
Payments on long-term debt	(943)	(415)
Proceeds from exercised stock options	4,342	12,936
Tax benefit from exercise of stock options	5,086	20,625
Repurchase of treasury stock	(61,310)	(5,885)
Other financing activities		(2,500)
Net cash (used in) provided by financing activities	(67,553)	13,264
Effect of exchange rate on cash and cash equivalents	248	(236)
Net increase in cash and cash equivalents	17,623	73,136
Beginning balance, cash and cash equivalents	158,541	128,438
Ending balance, cash and cash equivalents	$ 176,164	$ 201,574