Income Taxes (Components Of Deferred Tax Assets And Liabilities) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Income Taxes [Abstract]
Deferred rent	$ 623	$ 804
Accrued vacation	1,926	1,492
Accrued bonus	4,342	5,601
Deferred compensation	1,451	1,459
Inventory items	7,072	4,962
Allowance for doubtful accounts and other receivables	355	241
Other accruals	7,355	6,796
Equity based compensation expense	16,124	16,463
Unrealized gain on securities	288	76
Unrealized loss on other investments	0	570
Net operating loss carry-forwards	4,511	8,065
Valuation allowance	(267)	(267)	0	0
Total deferred tax assets	43,780	46,262
Unrealized loss on other investments	(931)	0
Unrealized loss on securities	0	(42)
Depreciation and amortization	(17,052)	(9,296)
Total deferred tax liabilities	(17,983)	(9,338)
Net deferred tax assets	$ 25,797	$ 36,924