Income Taxes (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
United States	$ 178,497,000	$ 158,851,000	$ 144,578,000
Foreign	2,888,000	(113,000)	(6,178,000)
Total	181,385,000	158,738,000	138,400,000
Current [Abstract]
Federal	54,447,000	49,425,000	43,871,000
State and other	9,126,000	7,486,000	5,958,000
Current tax	63,573,000	56,911,000	49,829,000
Deferred [Abstract]
Federal	6,942,000	4,905,000	6,071,000
State and other	44,000	(226,000)	844,000
Deferred tax	6,986,000	4,679,000	6,915,000
Total	70,559,000	61,590,000	56,744,000
Reconciliation of U.S. federal statutory tax rate to effective tax rate [Abstract]
Federal statutory rate (in hundredths)	35.00%	35.00%	35.00%
Change in valuation allowance (in hundredths)	0.43%	0.57%	1.97%
Other, primarily state income tax rate (in hundredths)	3.47%	3.23%	4.03%
Total effective tax rate (in hundredths)	38.90%	38.80%	41.00%
Deferred tax assets [Abstract]
Product inventories	6,583,000	6,476,000
Accrued expenses	3,168,000	4,072,000
Allowance for doubtful accounts	172,000	346,000
Total current	9,923,000	10,894,000
Less: Valuation Allowance, Current	(1,596,000)	(1,691,000)
Component reclassified for net presentation	(5,210,000)	(3,746,000)
Total current, net	3,117,000	5,457,000
Leases	1,763,000	1,805,000
Share-based compensation	14,483,000	15,579,000
Uncertain tax positions	1,641,000	1,343,000
Net operating losses	5,494,000	4,709,000
Interest rate swaps	861,000	667,000
Equity losses in unconsolidated investments	5,653,000	5,653,000
Other	1,009,000	953,000
Total noncurrent	30,904,000	30,709,000
Less: Valuation allowance, non-current	(9,551,000)	(8,672,000)
Component reclassified for net presentation	(20,462,000)	(21,253,000)
Total non-current, net	891,000	784,000
Total deferred tax assets	4,008,000	6,241,000
Deferred tax liabilities [Abstract]
Trade discounts on purchases	2,836,000	2,022,000
Prepaid expenses	2,374,000	1,724,000
Total current	5,210,000	3,746,000
Component reclassified for net presentation	(5,210,000)	(3,746,000)
Total current, net	0	0
Intangible assets, primarily goodwill	36,927,000	33,659,000
Depreciation	7,039,000	6,702,000
Total non-current	43,966,000	40,361,000
Component reclassified for net presentation	(20,462,000)	(21,253,000)
Total non-current, net	23,504,000	19,108,000
Total deferred tax liabilities	23,504,000	19,108,000
Net deferred tax liability	(19,496,000)	(12,867,000)
Loss Carryforwards [Line Items]
Excess Tax Benefit (Tax Deficiency) from Share-based Compensation, Financing Activities	5,524,000	4,611,000	4,487,000
Uncertain tax positions activity [Roll Forward]
Beginning balance	3,837,000	3,504,000	4,715,000
Increases for tax positions taken during a prior period	0	0	0
Increases for tax positions taken during the current period	1,664,000	1,140,000	972,000
Decreases resulting from the expiration of the statute of limitations	811,000	807,000	2,123,000
Decreases relating to settlements	0	0	60,000
Ending balance	4,690,000	3,837,000	3,504,000
Unrecognized tax benefits that, if recognized, would decrease the effective tax rate	3,048,000	2,494,000
Interest (income) expense related to unrecognized tax benefits		(157,000)	(291,000)
Accrued interest on unrecognized tax benefits	393,000	354,000
Capital Loss Carryforward [Member]
Loss Carryforwards [Line Items]
Deferred tax asset, valuation allowance	5,653,000
Capital loss carryforward, LAC	14,400,000
International Subsidiaries [Member]
Loss Carryforwards [Line Items]
Tax loss carry-forwards	19,874,000
Deferred tax asset, valuation allowance	$ 5,494,000	$ 4,709,000