Note 2 - Stock-based Compensation - RSU Summary (Details)	9 Months Ended
	Sep. 30, 2016 $ / shares shares
Time-Based RSUs [Member]
Beginning balance (in shares)	499,000
Weighted-Average Grant Date Fair Value Per Share (in dollars per share) | $ / shares	$ 40.75
Granted (in shares)	129,000
Weighted-Average Grant Date Fair Value Per Share (in dollars per share) | $ / shares	$ 62.54
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	129,000
Released (in shares)	(202,000)
Weighted-Average Grant Date Fair Value Per Share (in dollars per share) | $ / shares	$ 35.88
Forfeited (in shares)	(23,000)
Weighted-Average Grant Date Fair Value Per Share (in dollars per share) | $ / shares	$ 43.83
Ending balance (in shares)	403,000
Weighted-Average Grant Date Fair Value Per Share (in dollars per share) | $ / shares	$ 50.05
PSUs and MPSUs [Member]
Beginning balance (in shares)	1,933,000
Weighted-Average Grant Date Fair Value Per Share (in dollars per share) | $ / shares	$ 38.99
Granted (in shares)	1,288,000	[1]
Weighted-Average Grant Date Fair Value Per Share (in dollars per share) | $ / shares	$ 41.07
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	1,288,000	[1]
Performance adjustment (in shares)	(23,000)	[2]
Weighted-Average Grant Date Fair Value Per Share (in dollars per share) | $ / shares	$ 40.05
Released (in shares)	(649,000)
Weighted-Average Grant Date Fair Value Per Share (in dollars per share) | $ / shares	$ 29.86
Forfeited (in shares)	(129,000)
Weighted-Average Grant Date Fair Value Per Share (in dollars per share) | $ / shares	$ 36.82
Ending balance (in shares)	2,420,000
Weighted-Average Grant Date Fair Value Per Share (in dollars per share) | $ / shares	$ 42.65
MSUs [Member]
Beginning balance (in shares)	1,800,000
Weighted-Average Grant Date Fair Value Per Share (in dollars per share) | $ / shares	$ 23.57
Forfeited (in shares)	(180,000)
Weighted-Average Grant Date Fair Value Per Share (in dollars per share) | $ / shares	$ 23.57
Ending balance (in shares)	1,620,000
Weighted-Average Grant Date Fair Value Per Share (in dollars per share) | $ / shares	$ 23.57
Beginning balance (in shares)	4,232,000
Weighted-Average Grant Date Fair Value Per Share (in dollars per share) | $ / shares	$ 32.64
Granted (in shares)	1,417,000
Weighted-Average Grant Date Fair Value Per Share (in dollars per share) | $ / shares	$ 43.03
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	1,417,000
Performance adjustment (in shares)	(23,000)
Weighted-Average Grant Date Fair Value Per Share (in dollars per share) | $ / shares	$ 40.05
Released (in shares)	(851,000)
Weighted-Average Grant Date Fair Value Per Share (in dollars per share) | $ / shares	$ 31.29
Forfeited (in shares)	(332,000)
Weighted-Average Grant Date Fair Value Per Share (in dollars per share) | $ / shares	$ 30.14
Ending balance (in shares)	4,443,000
Weighted-Average Grant Date Fair Value Per Share (in dollars per share) | $ / shares	$ 36.36

[1] Amount reflects the maximum number of awards that can be earned assuming the achievement of the highest level of performance conditions.

[2] Amount reflects the net adjustment to the number of awards that have not been earned or may not be earned based on management's probability assessment at each reporting period.