Note 6 - Stockholder's Equity (Details) (USD $)	1 Months Ended	3 Months Ended	12 Months Ended					1 Months Ended		12 Months Ended		12 Months Ended		1 Months Ended	12 Months Ended							1 Months Ended						12 Months Ended					1 Months Ended				12 Months Ended					1 Months Ended								12 Months Ended				1 Months Ended		12 Months Ended	1 Months Ended		12 Months Ended
	Dec. 31, 2012	Dec. 31, 2012	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011	Feb. 28, 2014 Subsequent Event [Member] 2012 Time-Based RSUs and PSUs [Member] Executive Officer [Member]	Feb. 28, 2013 Remaining Shares [Member] 2013 Non-Executive PSUs [Member] Non-Executive Employees [Member]	Dec. 31, 2013 Maximum Annual Increase [Member] Two Thousand Four Employee Stock Purchase Plan [Member]	Apr. 30, 2013 2014 Plan [Member]	Dec. 31, 2012 Restricted Stock [Member] Minimum [Member]	Dec. 31, 2012 Restricted Stock [Member] Maximum [Member]	Dec. 28, 2012 Restricted Stock Units (RSUs) [Member]	Dec. 28, 2012 Restricted Stock Units (RSUs) [Member]	Dec. 31, 2013 Time-Based RSU's and PSUs [Member]	Dec. 31, 2012 Time-Based RSU's and PSUs [Member]	Dec. 31, 2011 Time-Based RSU's and PSUs [Member]	Dec. 31, 2013 Time-Based RSUs, PSUs, MSUs [Member]	Dec. 31, 2013 2013 MSUs [Member]	Dec. 31, 2013 2013 MSUs [Member] Maximum [Member]	Feb. 28, 2013 2013 Time-Based RSUs and PSUs [Member] Executive Officer [Member]	Feb. 28, 2013 Time-Based RSUs [Member] Executive Officer [Member]	Feb. 28, 2012 Time-Based RSUs [Member] Executive Officer [Member]	Feb. 28, 2013 Time-Based RSUs [Member] Non-Executive Employees [Member]	Apr. 30, 2012 Time-Based RSUs [Member] Non-Executive Employees [Member]	Feb. 28, 2011 Time-Based RSUs [Member] Chief Executive Officer [Member]	Dec. 31, 2013 Time-Based RSUs [Member]		Dec. 31, 2012 Time-Based RSUs [Member]		Dec. 31, 2011 Time-Based RSUs [Member]	Feb. 28, 2013 PSUs [Member] Executive Officer [Member]	Feb. 28, 2012 PSUs [Member] Executive Officer [Member]	Feb. 28, 2013 PSUs [Member] Non-Executive Employees [Member]	Apr. 30, 2012 PSUs [Member] Non-Executive Employees [Member]	Dec. 31, 2013 PSUs [Member]		Dec. 31, 2012 PSUs [Member]		Dec. 31, 2011 PSUs [Member]	Feb. 28, 2013 2013 Non-Executive PSUs [Member] Non-Executive Employees [Member]	Feb. 28, 2013 2013 Non-Executive PSUs [Member] Minimum [Member] Non-Executive Employees [Member]	Feb. 28, 2013 2013 Non-Executive PSUs [Member] Maximum [Member] Non-Executive Employees [Member]	Feb. 28, 2012 2012 Time-Based RSUs and PSUs [Member] Executive Officer [Member]	Apr. 30, 2012 2012 Non-Executive PSUs [Member] Non-Executive Employees [Member]	Apr. 30, 2012 2012 Non-Executive PSUs [Member] Minimum [Member] Non-Executive Employees [Member]	Apr. 30, 2012 2012 Non-Executive PSUs [Member] Maximum [Member] Non-Executive Employees [Member]	Feb. 28, 2010 2010 Executive PSUs [Member] Executive Officer [Member]	Dec. 31, 2013 Unvested Options [Member]	Dec. 31, 2013 Employee Stock Option [Member]	Dec. 31, 2012 Employee Stock Option [Member]	Dec. 31, 2011 Employee Stock Option [Member]	Dec. 31, 2012 2004 Plan [Member]	Jan. 31, 2005 2004 Plan [Member]	Dec. 31, 2013 2004 Plan [Member]	Nov. 30, 2004 2004 Plan [Member] Minimum [Member]	Nov. 30, 2004 2004 Plan [Member] Maximum [Member]	Dec. 31, 2013 ESPP [Member]	Dec. 31, 2013 Two Thousand Four Employee Stock Purchase Plan [Member]	Dec. 31, 2012 Two Thousand Four Employee Stock Purchase Plan [Member]	Dec. 31, 2011 Two Thousand Four Employee Stock Purchase Plan [Member]
Note 6 - Stockholder's Equity (Details) [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period									2 years													2 years	2 years	2 years	4 years	4 years	2 years																			2 years			4 years								2 years	10 years
Share-Based Compensation Arrangement by Share Based Payment Award Options Percent Increases in Period																																																							5.00%
Share-Based Compensation Arrangement by Share Based Payment Award Options, Maximum Increase in Period																																																							2,400,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized										1,000,000																																														1,800,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant																																																								3,800,000				4,800,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized											5,500,000										1,800,000
Common Stock, Dividends, Per Share, Declared (in Dollars per share)	$ 1.00
Common Stock, Dividends, Per Share, Cash Paid (in Dollars per share)	$ 35,700,000
Share-Based Compensation Arrangement by Share Based Payment Award Share Increase Modification Ratio	1.0471														1.0471
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross			171,484		178,484	[1]	152,500																																															171,484
Allocated Share-based Compensation Expense (in Dollars)		$ 2,800,000			$ 2,900,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Stock Options (in Dollars)	100,000	100,000			100,000
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term												1 year 328 days																																								4 years 36 days	4 years 36 days
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate													41.00%							38.69%																																53.40%	52.90%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate					0.30%															1.60%																																0.60%	1.10%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate					0.00%															0.00%																															0.00%
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period			2,973,714	[2]	1,579,880	[2],[3]	853,480	139,000						73,805						360,000		294,000			124,000	220,000	153,000	298,908	[2]	617,084	[2],[3]	853,480			91,000	125,000	874,806	[2]	962,796	[2],[3]	0	215,000			413,000	345,000			416,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized (in Dollars)			66,000											1,500,000	1,500,000				47,700,000																															500,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value, Vested (in Dollars)																18,600,000	10,500,000	5,800,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value, Outstanding (in Dollars)																			124,200,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition			2 months																7 years																															1 year
Share Price (in Dollars per share)																				$ 31.73
Share-Based Compensation Arrangement by Share Based Payment Award Equity Instruments Other Than Options Grants In Period Percentage																							25.00%	50.00%									75.00%	50.00%
Share Based Compensation Share Based Payment Other Than Options Percentage Allowed																											100.00%						300.00%										200.00%	300.00%	300.00%		200.00%	300.00%
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value (in Dollars)			27,800,000		10,000,000		5,800,000																																																					800,000	1,000,000	300,000
Proceeds from Stock Options Exercised (in Dollars)			37,900,000		13,400,000		4,700,000
Share-based Compensation Arrangement by Share-based Payment Award, Maximum Number of Shares Per Employee																																																											2,000
Share Based Compensation Arrangement By Share Based Payment Award Maximum Amount Per Employee																																																											$25,000
Share-Based Compensation Arrangement By Share Based Payment Award Number Of Additional Shares Percentage Authorized																																																												2.00%
Stock Issued During Period, Shares, Employee Stock Purchase Plans																																																												111,000	152,000	150,000
Proceeds from Stock Plans (in Dollars)			$ 2,145,000		$ 1,852,000		$ 1,773,000

[1] Includes 171,484 options granted as a result of the equity award modification discussed above.

[2] The number of PSUs and MSUs granted reflects the maximum number of shares that can be earned under the programs.

[3] Includes a total of 73,805 shares granted as a result of the equity award modifications discussed above.