Condensed Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Cash flows from operating activities:
Net income	$ 35,959	$ 20,073
Adjustments to reconcile net income to cash flows provided by operating activities:
Depreciation and amortization	10,943	9,802
Stock-based compensation expense	3,140	3,063
Other non-cash items	(166)	153
Changes in assets and liabilities, net of acquisitions of businesses:
Accounts receivable, net	(63,286)	(51,811)
Inventories, net	8,497	(3,505)
Prepaid expenses and other assets	(2,197)	(344)
Accounts payable, trade	18,692	13,678
Accrued expenses and other liabilities	31,929	16,024
Net cash flows provided by operating activities	43,511	7,133
Cash flows from investing activities:
Capital expenditures	(6,271)	(8,593)
Acquisitions of businesses	(18,100)	(2,723)
Proceeds from sales of fixed assets	234	68
Other investing activities	(151)	(177)
Net cash flows used for investing activities	(24,288)	(11,425)
Cash flows from financing activities:
Exercise of stock-based awards, net of shares tendered for payment of taxes	(3,196)	(1,847)
Proceeds from line of credit borrowings	81,458	175,350
Repayments under line of credit borrowings	(81,458)	(191,000)
Proceeds from shelf-loan borrowing	0	50,000
Payment of contingent consideration related to acquisitions	(415)	(127)
Other financing activities	0	(161)
Net cash flows (used for) provided by financing activities	(3,611)	32,215
Net increase in cash	15,612	27,923
Cash and cash equivalents at beginning of period	12,305	4
Cash and cash equivalents at end of period	27,917	27,927
Cash paid during the period for:
Interest	521	173
Income taxes, net of refunds	$ 122	$ 84