CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOW (UNAUDITED) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Operating activities
Net income	$ 42,618	$ 39,842
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization	7,680	7,001
Stock-based compensation expense	2,826	2,091
Deferred income taxes	(869)	(1,142)
Changes in operating assets and liabilities:
Trade receivables, net	14,680	46,162
Inventories, net	(26,333)	(11,683)
Prepaids and other assets	(5,096)	434
Excess tax benefits of stock options and awards	(49)	(606)
Accounts payable and accrued expenses	13,146	(7,116)
Net cash provided by operating activities	48,603	74,983
Investing activities
Purchase of property, plant and equipment	(13,220)	(12,070)
Proceeds from sale of equipment	356	166
Net cash used in investing activities	(12,864)	(11,904)
Financing activities
Proceeds from exercise of stock options	463	3,067
Excess tax benefits of stock options and awards	49	606
Net cash provided by financing activities	512	3,673
Effect of exchange rate changes on cash activities	331	(4,969)
Increase in cash and cash equivalents	36,582	61,783
Cash and cash equivalents at beginning of period	384,356	257,191
Cash and cash equivalents at end of period	$ 420,938	$ 318,974