Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Cash flows from operating activities:
Net income	$ 37,340	$ 30,059	$ 28,034
Adjustments to reconcile net income to cash flows provided by operating activities:
Depreciation and amortization	25,665	20,522	17,087
Stock-based compensation expense	6,318	4,587	4,176
Deferred taxes	(668)	821	(1,438)
Other non-cash items	654	1,570	(613)
Changes in assets and liabilities, net of acquisitions of businesses:
Accounts receivable, net	774	(5,007)	(341)
Inventories	(4,727)	(14,738)	(11,757)
Prepaid expenses and other assets	(10,738)	(1,848)	(951)
Accounts payable	5,983	4,391	3,838
Accrued expenses and other liabilities	12,088	(3,526)	4,028
Net cash flows provided by operating activities	72,689	36,831	42,063
Cash flows from investing activities:
Capital expenditures	(32,026)	(24,317)	(10,148)
Acquisitions of businesses	(1,473)	(50,302)	(21,900)
Proceeds from sales of fixed assets	5,420	1,338	1,788
Proceeds from maturity of short-term investments		5,000	29,000
Purchase of short-term investments			(20,985)
Other investing activities	(119)	(843)	(303)
Net cash flows used for investing activities	(28,198)	(69,124)	(22,548)
Cash flows from financing activities:
Exercise of stock options and deferred stock units	8,217	1,188	1,082
Proceeds from line of credit borrowings	52,227	130,500
Repayments under line of credit borrowings	(52,227)	(130,500)
Payment of special dividend	(45,038)		(33,032)
Payment of contingent consideration related to acquisitions	(4,315)	(398)	(8)
Purchase of treasury stock		(626)	(1,041)
Other financing activities		(167)	(1)
Net cash flows used for financing activities	(41,136)	(3)	(33,000)
Net increase (decrease) in cash	3,355	(32,296)	(13,485)
Cash and cash equivalents at beginning of period	6,584	38,880	52,365
Cash and cash equivalents at end of period	9,939	6,584	38,880
Supplemental disclosure of cash flow information:
Interest	369	284	311
Income taxes, net of refunds	$ 24,145	$ 18,909	$ 19,862