Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
United States	$ 203,269	$ 178,497	$ 158,851
Foreign	4,881	2,888	(113)
Total	208,150	181,385	158,738
Current [Abstract]
Federal	65,676	54,447	49,425
State and other	10,263	9,126	7,486
Current tax	75,939	63,573	56,911
Deferred [Abstract]
Federal	4,568	6,942	4,905
State and other	(370)	44	(226)
Deferred tax	4,198	6,986	4,679
Total	$ 80,137	$ 70,559	$ 61,590
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)	0.20%	0.43%	0.57%
Other, primarily state income tax rate (in hundredths)	3.30%	3.47%	3.23%
Total effective tax rate (in hundredths)	38.50%	38.90%	38.80%
Deferred tax assets [Abstract]
Product inventories	$ 7,101	$ 6,583
Accrued expenses	3,303	3,168
Allowance for doubtful accounts	606	172
Total current	11,010	9,923
Less: Valuation Allowance, Current	0	(1,596)
Component reclassified for net presentation	(5,480)	(5,210)
Total current, net	5,530	3,117
Leases	1,786	1,763
Share-based compensation	13,422	14,483
Uncertain tax positions	2,092	1,641
Net operating losses	5,485	5,494
Interest rate swaps	1,513	861
Equity losses in unconsolidated investments	0	5,653
Other	1,159	1,009
Total noncurrent	25,457	30,904
Less: Valuation allowance, non-current	(5,485)	(9,551)
Component reclassified for net presentation	(18,755)	(20,462)
Total non-current, net	1,217	891
Total deferred tax assets	6,747	4,008
Deferred tax liabilities [Abstract]
Trade discounts on purchases	3,001	2,836
Prepaid expenses	2,479	2,374
Total current	5,480	5,210
Component reclassified for net presentation	(5,480)	(5,210)
Total current, net	0	0
Intangible assets, primarily goodwill	40,197	36,927
Depreciation	8,366	7,039
Total non-current	48,563	43,966
Component reclassified for net presentation	(18,755)	(20,462)
Total non-current, net	29,808	23,504
Total deferred tax liabilities	29,808	23,504
Net deferred tax liability	(23,061)	(19,496)
Loss Carryforwards [Line Items]
Excess Tax Benefit (Tax Deficiency) from Share-based Compensation, Financing Activities	7,706	5,524	$ 4,611
Uncertain tax positions activity [Roll Forward]
Beginning balance	4,690	3,837	3,504
Increases for tax positions taken during a prior period	410	0	0
Increases for tax positions taken during the current period	1,782	1,664	1,140
Decreases resulting from the expiration of the statute of limitations	904	811	807
Decreases relating to settlements	0	0	0
Ending balance	5,978	4,690	3,837
Unrecognized tax benefits that, if recognized, would decrease the effective tax rate	3,886	3,048
Interest (income) expense related to unrecognized tax benefits	136		$ (157)
Accrued interest on unrecognized tax benefits	529	393
Capital Loss Carryforward [Member]
Loss Carryforwards [Line Items]
Deferred tax asset, valuation allowance		5,653
Capital loss carryforward, LAC		14,385
International Subsidiaries [Member]
Loss Carryforwards [Line Items]
Tax loss carry-forwards	21,408
Deferred tax asset, valuation allowance	$ 5,485	$ 5,494