Condensed Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Cash flows from operating activities:
Net income	$ 8,035	$ 19,833
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization, and accretion	8,418	5,877
Provision for (recovery of) doubtful accounts, net	204	(171)
Write-down of inventory	862	1,160
Stock compensation	3,970	2,827
Other	165	131
Changes in operating assets and liabilities:
Trade accounts receivable	85,010	38,607
Inventories	43,955	16,718
Prepaid expenses and other current assets	4,198	(5,342)
Other assets	(2,117)	(2,695)
Trade accounts payable	(69,223)	(24,063)
Contingent consideration	(959)
Accrued expenses	(27,961)	(27,976)
Income taxes payable	(30,318)	(22,773)
Long-term liabilities	2,831	1,450
Net cash provided by operating activities	27,070	3,583
Cash flows from investing activities:
Purchases of property and equipment	(11,188)	(5,060)
Purchases of intangible assets		(4,148)
Net cash used in investing activities	(11,188)	(9,208)
Cash flows from financing activities:
Cash paid for shares withheld for taxes	(3,353)	(5,286)
Excess tax benefits from stock compensation	461	3,393
Cash paid for repurchases of common stock	(19,999)
Contingent consideration paid	(29,041)
Net cash used in financing activities	(51,932)	(1,893)
Effect of exchange rates on cash	1,015	192
Net change in cash and cash equivalents	(35,035)	(7,326)
Cash and cash equivalents at beginning of period	263,606	445,226
Cash and cash equivalents at end of period	228,571	437,900
Cash paid during the period for:
Income taxes	34,025	27,867
Interest	47	6
Non-cash investing activity:
Accruals for purchases of property and equipment	1,090	148
Accruals for asset retirement obligations	33
Non-cash financing activity:
Accruals for shares withheld for taxes	$ 1,195	$ 1,891