Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Operating activities
Net income	$ 143,654	$ 149,625
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization	22,777	22,774
Stock-based compensation expense	9,794	8,640
Loss (gain) on sale of equipment	73	(199)
Deferred income taxes	(7,420)	1,879
Changes in operating assets and liabilities:
Trade receivables, net	60,329	(55,169)
Inventories, net	8,993	(44,047)
Prepaids and other assets	(8,747)	(2,722)
Excess tax benefits of stock options and awards	(57)	(309)
Accounts payable and accrued expenses	(70,658)	22,112
Net cash provided by operating activities	158,738	102,584
Investing activities
Purchase of property, plant and equipment	(16,746)	(31,164)
Proceeds from sale of equipment	183	543
Net cash used in investing activities	(16,563)	(30,621)
Financing activities
Repurchase of common stock	(40,911)	(140,261)
Proceeds from exercise of stock options	1,952	1,864
Excess tax benefits of stock options and awards	57	309
Net cash used in financing activities	(38,902)	(138,088)
Effect of exchange rate changes on cash activities	(5,009)	(3,267)
Increase (decrease) in cash and cash equivalents	98,264	(69,392)
Cash and cash equivalents at beginning of period	298,705	384,356
Cash and cash equivalents at end of period	$ 396,969	$ 314,964