Condensed 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	$ 1,007	$ 8,035
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion	8,970	8,418
Change in fair value of contingent consideration	979
(Recovery of) provision for doubtful accounts	(314)	204
Stock compensation	2,404	3,970
Other	(111)	165
Changes in operating assets and liabilities net of assets and liabilities acquired in acquisition of businesses:
Trade accounts receivable	80,751	85,010
Inventories	43,076	44,817
Prepaid expenses and other current assets	(7,413)	4,198
Income taxes receivable	(4,799)
Other assets	44	(2,117)
Trade accounts payable	(72,295)	(69,223)
Contingent consideration	(6,458)	(959)
Accrued expenses	(9,169)	(27,961)
Income taxes payable	(21,735)	(30,318)
Long-term liabilities	830	2,831
Net cash provided by operating activities	15,767	27,070
Cash flows from investing activities:
Purchases of property and equipment	(12,104)	(11,188)
Net cash used in investing activities	(12,104)	(11,188)
Cash flows from financing activities:
Cash paid for shares withheld for taxes	(1,804)	(3,353)
Excess tax benefits from stock compensation	270	461
Cash paid for repurchases of common stock		(19,999)
Proceeds from issuance of short-term borrowings	10,000
Cash paid for repayment of short-term borrowings	(33,000)
Contingent consideration paid	(22,628)	(29,041)
Net cash used in financing activities	(47,162)	(51,932)
Effect of exchange rates on cash	(2,157)	1,015
Net change in cash and cash equivalents	(45,656)	(35,035)
Cash and cash equivalents at beginning of period	110,247	263,606
Cash and cash equivalents at end of period	64,591	228,571
Cash paid during the period for:
Income taxes	27,885	34,025
Interest	68	47
Non-cash investing activity:
Accruals for purchases of property and equipment	1,263	1,090
Accruals for asset retirement obligations	23	33
Non-cash financing activity:
Accruals for shares withheld for taxes	$ 1,365	$ 1,195