CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Cash flows from operating activities:
Net income	$ 145,689	$ 129,014	$ 201,858
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization, and accretion	41,439	33,367	28,977
Change in fair value of contingent consideration	1,815	8,659
Provision for (recovery of) doubtful accounts, net	125	2,128	(704)
Deferred tax provision	(4,092)	(5,657)	(67)
Stock compensation	13,136	14,661	14,803
Other	1,306	1,229	2,735
Changes in operating assets and liabilities, net of assets and liabilities acquired in the acquisition of businesses:
Trade accounts receivable	6,618	491	(63,199)
Inventories	40,580	(46,903)	(120,730)
Prepaid expenses and other current assets	(58,554)	23,511	(75,525)
Other assets	(4,290)	(3,028)	(5,385)
Trade accounts payable	21,251	18,932	38,237
Contingent consideration	(6,458)	(959)
Accrued expenses	33,556	(9,983)	850
Income taxes payable	24,386	(5,820)	5,722
Long-term liabilities	5,618	4,264	2,519
Net cash provided by operating activities	262,125	163,906	30,091
Cash flows from investing activities:
Purchases of property and equipment	(79,829)	(61,575)	(55,538)
Acquisitions of businesses and equity method investment	0	(8,829)	(125,203)
Purchases of intangible assets	(5,368)	(4,958)	(4,025)
Net cash used in investing activities	(85,197)	(75,362)	(184,766)
Cash flows from financing activities:
Proceeds from issuance of short-term borrowings	320,728	307,000	45,000
Repayments of short-term borrowings	(344,000)	(274,000)	(45,000)
Cash paid for shares withheld for taxes	(6,736)	(6,535)	(22,634)
Excess tax benefit from stock compensation	2,071	2,457	15,330
Cash received from issuances of common stock	52	0	62
Loan origination costs on short-term borrowings	0	(1,807)
Contingent consideration paid	(22,628)	(29,041)
Cash paid for noncontrolling interest	0	(20,000)
Cash paid for repurchases of common stock	0	(220,695)	(19,918)
Net cash used in financing activities	(50,513)	(242,621)	(27,160)
Effect of exchange rates on cash	463	718	215
Net change in cash and cash equivalents	126,878	(153,359)	(181,620)
Cash and cash equivalents at beginning of year	110,247	263,606	445,226
Cash and cash equivalents at end of year	237,125	110,247	263,606
Cash paid during the year for:
Income taxes	39,122	66,899	62,405
Interest	2,586	3,338	88
Non-cash investing and financing activity:
Deferred purchase payments for acquisition of business	0	3,671
Accruals for purchases of property and equipment	2,283	489	3,268
Contingent consideration arrangement for acquisition of business	0	1,128	88,100
Accruals for asset retirement obligations	1,936	526	236
Accruals for shares withheld for taxes	3,702	1,804	2,460
Write-off for shares exercised with a tax deficit	$ 1,752	$ 2,838