Condensed Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Cash flows from operating activities:
Net income	$ 16,164	$ 8,372
Adjustments to reconcile net income to cash flows provided by (used for) operating activities:
Depreciation and amortization	7,240	6,552
Stock-based compensation expense	2,625	3,155
Other non-cash items	679	509
Changes in assets and liabilities, net of acquisitions of businesses:
Accounts receivable, net	(42,790)	(32,403)
Inventories, net	4,417	(12,840)
Prepaid expenses and other assets	4,743	3,880
Accounts payable, trade	23,374	18,531
Accrued expenses and other liabilities	10,858	3,192
Net cash flows provided by (used for) operating activities	27,310	(1,052)
Cash flows from investing activities:
Capital expenditures	(6,824)	(8,938)
Acquisitions of businesses	(46,657)	0
Proceeds from sales of fixed assets	707	31
Other investing activities	(4)	(29)
Net cash flows used for investing activities	(52,778)	(8,936)
Cash flows from financing activities:
Exercise of stock options and deferred stock units	3,320	4,959
Proceeds from line of credit borrowings	79,469	96,333
Repayments under line of credit borrowings	(69,469)	(96,333)
Payment of special dividend	(46,706)	0
Payment of contingent consideration related to acquisitions	(1,098)	(875)
Other financing activities	(196)	0
Net cash flows (used for) provided by financing activities	(34,680)	4,084
Net decrease in cash	(60,148)	(5,904)
Cash and cash equivalents at beginning of period	66,280	9,939
Cash and cash equivalents at end of period	6,132	4,035
Cash paid during the period for:
Interest	73	64
Income taxes, net of refunds	$ 922	$ 16