Condensed Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Cash flows from operating activities:
Net income	$ 73,528	$ 40,942
Adjustments to reconcile net income to cash flows provided by operating activities:
Depreciation and amortization	22,190	19,855
Stock-based compensation expense	7,274	7,069
Other non-cash items	809	162
Changes in assets and liabilities, net of acquisitions of businesses:
Accounts receivable, net	(58,777)	(30,536)
Inventories, net	25,590	(24,361)
Prepaid expenses and other assets	(4,199)	2,333
Accounts payable, trade	21,496	1,250
Accrued expenses and other liabilities	45,102	19,645
Net cash flows provided by operating activities	133,013	36,359
Cash flows from investing activities:
Capital expenditures	(12,971)	(14,668)
Acquisitions of businesses, net of cash acquired	(34,237)	(25,058)
Proceeds from sales of fixed assets	337	1,958
Other investing activities	(237)	(213)
Net cash flows used for investing activities	(47,108)	(37,981)
Cash flows from financing activities:
Proceeds from Issuance of Shares under Incentive and Share-based Compensation Plans, Including Stock Options	(1,144)	(688)
Proceeds from line of credit borrowings	81,458	390,870
Repayments under line of credit borrowings	(81,458)	(376,520)
Proceeds from shelf-loan borrowing	0	50,000
Payment of dividends	(14,707)	(48,227)
Payment of contingent consideration related to acquisitions	(2,715)	(1,874)
Other financing activities	(1,084)	(161)
Net cash flows (used for) provided by financing activities	(19,650)	13,400
Net increase in cash	66,255	11,778
Cash and cash equivalents at beginning of period	12,305	4
Cash and cash equivalents at end of period	78,560	11,782
Cash paid during the period for:
Interest	1,082	788
Income taxes, net of refunds	$ 19,134	$ 8,613