Note 2 - Summary of Significant Accounting Policies (Detail) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Certificates of Deposit, at Carrying Value	$ 13,500,000	$ 15,500,000
Sales Revenue, Services, Net	570,569,000	470,756,000	410,857,000
Deferred Revenue	98,900,000
Deferred Finance Costs, Gross	8,500,000	1,000,000
Amortization of Intangible Assets	1,300,000	1,000,000	300,000
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months	1,100,000
Finite-Lived Intangible Assets, Amortization Expense, Year Two	900,000
Finite-Lived Intangible Assets, Amortization Expense, Year Three	900,000
Finite-Lived Intangible Assets, Amortization Expense, Year Four	400,000
Finite-Lived Intangible Assets, Amortization Expense, Year Five	300,000
Number of Operating Segments	6
Deferred Customer Acquisition Costs Noncurrent	9,785,000	1,452,000
Number of Customers who Represented Over Ten Percent of Accounts Receivable	1	1
Number of Grant of Restricted Shares that Vests All on Third Anniversary Date	1
Share-based Compensation	8,707,000	10,477,000	8,838,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Total Intrinsic Value	500,000	1,800,000	2,200,000
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized	15,200,000	20,000,000
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition	2 years 73 days	2 years 146 days
Amortization of Financing Costs	1,400,000	1,300,000	1,600,000
Recognition of Deferred Revenue	1,000,000	1,100,000	1,100,000
Advertising Expense	45,400,000	21,700,000	16,400,000
Advertising Revenue Cost	36,500,000	14,500,000	10,000,000
Shipping, Handling and Transportation Costs	2,800,000	2,900,000	2,200,000
Sale of Program Materials and Supplies [Member]
Sales Revenue, Services, Net	7,100,000	6,300,000	7,000,000
Fiscal Year Ending Dec 31, 2012 [Member]
Deferred Customer Acquisition Costs Amortization Expense Next Twelve Months	8,400,000
Fiscal Year Ending Dec 31, 2013 [Member]
Deferred Customer Acquisition Costs Amortization Expense Year Two	1,400,000
Administrative Expenses [Member]
Foreign Currency Transaction Gain (Loss), before Tax	400,000	(1,300,000)	(1,200,000)
Cost of Products [Member]
Foreign Currency Transaction Gain (Loss), before Tax	$ (1,000,000)	$ (100,000)	$ 800,000
Employees' Equity Plans [Member]
Common Stock, Capital Shares Reserved for Future Issuance (in Shares)	8,425,000
Directors' Plan [Member]
Common Stock, Capital Shares Reserved for Future Issuance (in Shares)	185,625
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	1 year
Share Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award Award Term	10 years
Non-qualified Share Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award Award Term	10 years
Minimum [Member]
Finite-Lived Intangible Asset, Useful Life	3 years
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	3 years
Maximum [Member]
Finite-Lived Intangible Asset, Useful Life	20 years
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	5 years