Condensed Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Cash flows from operating activities:
Net income	$ 50,270	$ 39,042
Adjustments to reconcile net income to cash flows provided by operating activities:
Depreciation and amortization	23,475	20,388
Stock-based compensation expense	7,909	8,224
Other non-cash items	2,837	1,787
Changes in assets and liabilities, net of acquisitions of businesses:
Accounts receivable, net	(27,162)	(32,829)
Inventories, net	(16,526)	1,246
Prepaid expenses and other assets	(3,668)	4,090
Accounts payable, trade	16,276	10,042
Accrued expenses and other liabilities	13,553	9,681
Net cash flows provided by operating activities	66,964	61,671
Cash flows from investing activities:
Capital expenditures	(30,032)	(26,080)
Acquisitions of businesses	(100,157)	(1,451)
Proceeds from note receivable	750	0
Proceeds from sales of fixed assets	3,344	1,381
Other investing activities	(66)	(117)
Net cash flows used for investing activities	(126,161)	(26,267)
Cash flows from financing activities:
Exercise of stock options and deferred stock units, net of shares tendered for payment	3,555	11,817
Proceeds from line of credit borrowings	330,346	135,452
Repayments under line of credit borrowings	(290,346)	(135,452)
Payment of special dividend	(46,706)	0
Payment of contingent consideration related to acquisitions	(3,732)	(4,287)
Other financing activities	(196)	0
Net cash flows (used for) provided by financing activities	(7,079)	7,530
Net (decrease) increase in cash	(66,276)	42,934
Cash and cash equivalents at beginning of period	66,280	9,939
Cash and cash equivalents at end of period	4	52,873
Cash paid during the period for:
Interest	409	226
Income taxes, net of refunds	$ 27,301	$ 19,276