Note 3 - Stock-based Compensation - RSU Summary (Details) shares in Thousands	9 Months Ended
	Sep. 30, 2022 $ / shares shares
Balance (in shares) | shares	2,509
Weighted-Average Grant Date Fair Value Per Share, ending balance (in dollars per share)	$ 136.87
Granted (in shares) | shares	606
Weighted-Average Grant Date Fair Value Per Share, granted (in dollars per share)	$ 347.57
Vested (in shares) | shares	(671)
Weighted-Average Grant Date Fair Value Per Share, vested (in dollars per share)	$ 102.22
Weighted-Average Grant Date Fair Value Per Share, vested (in dollars per share)	$ (102.22)
Forfeited (in shares) | shares	(13)
Weighted-Average Grant Date Fair Value Per Share, forfeited (in dollars per share)	$ 268.11
Balance (in shares) | shares	2,431
Weighted-Average Grant Date Fair Value Per Share, ending balance (in dollars per share)	$ 198.26
Time-Based RSUs [Member]
Balance (in shares) | shares	125
Weighted-Average Grant Date Fair Value Per Share, ending balance (in dollars per share)	$ 235.82
Granted (in shares) | shares	44
Weighted-Average Grant Date Fair Value Per Share, granted (in dollars per share)	$ 396.77
Vested (in shares) | shares	(53)
Weighted-Average Grant Date Fair Value Per Share, vested (in dollars per share)	$ 188.73
Weighted-Average Grant Date Fair Value Per Share, vested (in dollars per share)	$ (188.73)
Forfeited (in shares) | shares	(6)
Weighted-Average Grant Date Fair Value Per Share, forfeited (in dollars per share)	$ 308.76
Balance (in shares) | shares	110
Weighted-Average Grant Date Fair Value Per Share, ending balance (in dollars per share)	$ 318.11
PSUs and MPSUs [Member]
Balance (in shares) | shares	1,166
Weighted-Average Grant Date Fair Value Per Share, ending balance (in dollars per share)	$ 222.78
Granted (in shares) | shares	442	[1]
Weighted-Average Grant Date Fair Value Per Share, granted (in dollars per share)	$ 363.74
Vested (in shares) | shares	(375)
Weighted-Average Grant Date Fair Value Per Share, vested (in dollars per share)	$ 141.02
Weighted-Average Grant Date Fair Value Per Share, vested (in dollars per share)	$ (141.02)
Forfeited (in shares) | shares	(1)
Weighted-Average Grant Date Fair Value Per Share, forfeited (in dollars per share)	$ 374.87
Balance (in shares) | shares	1,232
Weighted-Average Grant Date Fair Value Per Share, ending balance (in dollars per share)	$ 298.24
MSUs [Member]
Balance (in shares) | shares	1,218
Weighted-Average Grant Date Fair Value Per Share, ending balance (in dollars per share)	$ 44.59
Granted (in shares) | shares	120
Weighted-Average Grant Date Fair Value Per Share, granted (in dollars per share)	$ 270.15
Vested (in shares) | shares	(243)
Weighted-Average Grant Date Fair Value Per Share, vested (in dollars per share)	$ 23.57
Weighted-Average Grant Date Fair Value Per Share, vested (in dollars per share)	$ (23.57)
Forfeited (in shares) | shares	(6)
Weighted-Average Grant Date Fair Value Per Share, forfeited (in dollars per share)	$ 216.37
Balance (in shares) | shares	1,089
Weighted-Average Grant Date Fair Value Per Share, ending balance (in dollars per share)	$ 73.23

[1] Amount reflects the number of awards that may ultimately be earned based on management’s probability assessment of the achievement of performance conditions at each reporting period.