Income Taxes (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Tax Disclosure [Abstract]
United States	$ 158,851	$ 144,578	$ 111,376
Foreign	(113)	(6,178)	5,727
Total	158,738	138,400	117,103
Current [Abstract]
Federal	49,425	43,871	32,850
State and other	7,486	5,958	7,675
Current tax	56,911	49,829	40,525
Deferred [Abstract]
Federal	4,905	6,071	4,754
State and other	(226)	844	40
Deferred tax	4,679	6,915	4,794
Total	61,590	56,744	45,319
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)	0.57%	1.97%	0.37%
Other, primarily state income tax rate (in hundredths)	3.23%	4.03%	3.33%
Total effective tax rate (in hundredths)	38.80%	41.00%	38.70%
Deferred tax assets [Abstract]
Product inventories	6,476	7,703
Accrued expenses	4,072	2,780
Allowance for doubtful accounts	346	420
Total current	10,894	10,903
Less: Valuation Allowance, Current	(1,691)	(1,584)
Component reclassified for net presentation	(3,746)	(4,133)
Total current, net	5,457	5,186
Leases	1,805	1,957
Share-based compensation	15,579	16,970
Uncertain tax positions	1,343	1,226
Net operating losses	4,709	6,703
Interest rate swaps	667	1,327
Equity losses in unconsolidated investments	5,653	5,653
Other	953	1,150
Total noncurrent	30,709	34,986
Less: Valuation allowance, non-current	(8,672)	(10,772)
Component reclassified for net presentation	(21,253)	(23,474)
Total non-current, net	784	740
Total deferred tax assets	6,241	5,926
Deferred tax liabilities [Abstract]
Trade discounts on purchases	2,022	2,681
Prepaid expenses	1,724	1,452
Total current	3,746	4,133
Component reclassified for net presentation	(3,746)	(4,133)
Total current, net	0	0
Intangible assets, primarily goodwill	33,659	30,645
Depreciation	6,702	6,282
Total non-current	40,361	36,927
Component reclassified for net presentation	(21,253)	(23,474)
Total non-current, net	19,108	13,453
Total deferred tax liabilities	19,108	13,453
Net deferred tax liability	(12,867)	(7,527)
Operating Loss Carryforwards [Line Items]
Tax loss carry-forwards	17,312
Excess Tax Benefit (Tax Deficiency) from Share-based Compensation, Financing Activities	4,611	4,487	3,118
Uncertain tax positions activity [Roll Forward]
Beginning balance	3,504	4,715	3,962
Increases for tax positions taken during a prior period	0	0	0
Increases for tax positions taken during the current period	1,140	972	914
Decreases resulting from the expiration of the statute of limitations	(807)	(2,123)	(46)
Decreases relating to settlements	0	(60)	(115)
Ending balance	3,837	3,504	4,715
Unrecognized tax benefits that, if recognized, would decrease the effective tax rate	2,494	2,277
Interest (income) expense related to unrecognized tax benefits	(157)	(291)	307
Accrued interest on unrecognized tax benefits	354	511
International Subsidiaries [Member]
Operating Loss Carryforwards [Line Items]
Deferred tax asset, valuation allowance	(4,709)	(6,703)
Investment in Lac [Member]
Operating Loss Carryforwards [Line Items]
Deferred tax asset, valuation allowance	$ (5,654)