Condensed Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash flows from operating activities:
Net income	$ 129,671	$ 74,345	$ 62,266
Adjustments to reconcile net income to cash flows provided by operating activities:
Depreciation and amortization	46,167	41,624	32,596
Stock-based compensation expense	15,420	14,043	10,817
Deferred taxes	(2,598)	1,062	(5,493)
Other non-cash items	1,540	1,335	2,796
Changes in assets and liabilities, net of acquisitions of businesses:
Accounts receivable, net	(13,899)	2,082	(606)
Inventories, net	(7,856)	(31,276)	(21,940)
Prepaid expenses and other assets	(15,553)	(2,249)	(4,610)
Accounts payable, trade	18,800	(21,783)	21,269
Accrued expenses and other liabilities	31,715	15,835	9,925
Net cash flows provided by operating activities	203,407	95,018	107,020
Cash flows from investing activities:
Capital expenditures	(44,671)	(28,989)	(42,458)
Acquisitions of businesses, net of cash acquired	(48,725)	(41,058)	(106,782)
Proceeds from note receivable	2,000	2,000	1,750
Proceeds from sales of fixed assets	698	2,337	3,587
Other investing activities	(1,009)	(406)	(171)
Net cash flows used for investing activities	(91,707)	(66,116)	(144,074)
Cash flows from financing activities:
Exercise of stock-based awards, net of shares tendered for payment of taxes	2,574	1,470	5,769
Proceeds from line of credit borrowings	81,458	614,629	425,330
Repayments under line of credit borrowings	(81,458)	(630,279)	(409,680)
Payment of dividends	(34,437)	(48,227)	(46,706)
Proceeds from shelf-loan borrowing	0	50,000	0
Payment of contingent consideration related to acquisitions	(4,944)	(3,974)	(3,739)
Other financing activities	(1,028)	(220)	(196)
Net cash flows used for financing activities	(37,835)	(16,601)	(29,222)
Net increase (decrease) in cash and cash equivalents	73,865	12,301	(66,276)
Cash and cash equivalents at beginning of year	12,305	4	66,280
Cash and cash equivalents at end of year	86,170	12,305	4
Cash paid during the year for:
Interest	1,992	2,113	641
Income taxes, net of refunds	$ 65,792	$ 33,782	$ 30,947