Income Taxes (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Income Taxes [Abstract]
United States	$ 111,376,000	$ 92,108,000	$ 76,941,000
Foreign	5,727,000	2,518,000	1,832,000
Total	117,103,000	94,626,000	78,773,000
Current [Abstract]
Federal	32,850,000	29,040,000	24,422,000
State and other	7,675,000	5,682,000	4,998,000
Current tax	40,525,000	34,722,000	29,420,000
Deferred [Abstract]
Federal	4,754,000	1,715,000	1,659,000
State and other	40,000	656,000	(122,000)
Deferred tax	4,794,000	2,371,000	1,537,000
Total	45,319,000	37,093,000	30,957,000
Reconciliation of U.S. federal statutory tax rate to effective tax rate [Abstract]
Federal statutory rate (in hundredths)	35.00%	35.00%	35.00%
Other, primarily state income tax rate (in hundredths)	3.70%	4.20%	4.30%
Total effective tax rate (in hundredths)	38.70%	39.20%	39.30%
Reduction in deferred tax liability			1,400,000
Deferred tax assets [Abstract]
Product inventories	8,075,000	8,085,000
Accrued expenses	2,885,000	1,272,000
Allowance for doubtful accounts	777,000	854,000
Total current	11,737,000	10,211,000
Leases	1,866,000	1,676,000
Share-based compensation	17,740,000	17,321,000
Uncertain tax positions	1,650,000	1,387,000
Net operating losses	3,972,000	3,537,000
Interest rate swaps	164,000	1,316,000
Equity losses in unconsolidated investments	5,653,000	5,653,000
Other	1,037,000	1,079,000
Total noncurrent	32,082,000	31,969,000
Less: Valuation allowance	9,625,000	9,190,000
Total non-current	22,457,000	22,779,000
Total deferred tax assets	34,194,000	32,990,000
Deferred tax liabilities [Abstract]
Trade discounts on purchases	1,944,000	2,159,000
Prepaid expenses	1,032,000	1,067,000
Total current	2,976,000	3,226,000
Intangible assets, primarily goodwill	27,108,000	24,330,000
Depreciation	5,885,000	1,263,000
Total non-current	32,993,000	25,593,000
Total deferred tax liabilities	35,969,000	28,819,000
Net deferred tax asset	(1,775,000)	4,171,000
Operating Loss Carryforwards [Line Items]
Deferred tax asset, valuation allowance	(9,625,000)	(9,190,000)
Uncertain tax positions activity [Roll Forward]
Beginning balance	3,962,000	4,550,000	3,887,000
Increases for tax positions taken during a prior period	0	114,000	579,000
Increases for tax positions taken during the current period	914,000	811,000	898,000
Decreases resulting from the expiration of the statute of limitations	(46,000)	(992,000)	(814,000)
Decreases relating to settlements	(115,000)	(521,000)	0
Ending balance	4,715,000	3,962,000	4,550,000
Unrecognized tax benefits that, if recognized, would decrease the effective tax rate	3,000,000	2,600,000
Interest expense related to unrecognized tax benefits	300,000	100,000
Accrued interest on unrecognized tax benefits	800,000	500,000
Investment in LAC [Member]
Deferred tax assets [Abstract]
Less: Valuation allowance	(5,700,000)
Operating Loss Carryforwards [Line Items]
Deferred tax asset, valuation allowance	5,700,000
International Subsidiaries [Member]
Deferred tax assets [Abstract]
Less: Valuation allowance	(4,000,000)	(3,500,000)
Operating Loss Carryforwards [Line Items]
Tax loss carry-forwards	13,100,000
Operating loss carry-forwards, valuation allowance,	4,000,000	3,500,000
Deferred tax asset, valuation allowance	4,000,000	3,500,000
Excess tax benefits on exercise of nonqualified stock options and lapse of restrictions on restricted stock awards	$ 3,100,000	$ 1,900,000