Note 8 - Stock-based Compensation - RSU Summary (Details) - $ / shares		12 Months Ended
		Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Balance (in shares)		2,086,000	2,659,000	2,509,000
Weighted-Average Grant Date Fair Value Per Share (in dollars per share)		$ 222.04	$ 176.5	$ 136.87
Granted (in shares)		402,000	363,000	1,001,000
Weighted-Average Grant Date Fair Value Per Share, granted (in dollars per share)		$ 584.49	$ 444.86	$ 215.63
Vested (in shares)		(778,000)	(911,000)	(837,000)
Weighted-Average Grant Date Fair Value Per Share, vested (in dollars per share)		$ 133.62	$ 177.54	$ 103.02
Forfeited (in shares)		(6,000)	(25,000)	(14,000)
Weighted-Average Grant Date Fair Value Per Share, forfeited (in dollars per share)		$ 432.32	$ 209.23	$ 275.47
Balance (in shares)		1,704,000	2,086,000	2,659,000
Weighted-Average Grant Date Fair Value Per Share (in dollars per share)		$ 347.01	$ 222.04	$ 176.5
Time-Based RSUs [Member]
Balance (in shares)		102,000	106,000	125,000
Weighted-Average Grant Date Fair Value Per Share (in dollars per share)		$ 411.11	$ 327.13	$ 235.82
Granted (in shares)		33,000	51,000	49,000
Weighted-Average Grant Date Fair Value Per Share, granted (in dollars per share)		$ 653.66	$ 472.38	$ 390.89
Vested (in shares)		(46,000)	(49,000)	(61,000)
Weighted-Average Grant Date Fair Value Per Share, vested (in dollars per share)		$ 385.06	$ 296.65	$ 193.18
Forfeited (in shares)		(4,000)	(6,000)	(7,000)
Weighted-Average Grant Date Fair Value Per Share, forfeited (in dollars per share)		$ 482.83	$ 387.61	$ 316
Balance (in shares)		85,000	102,000	106,000
Weighted-Average Grant Date Fair Value Per Share (in dollars per share)		$ 516.12	$ 411.11	$ 327.13
PSUs and MPSUs [Member]
Balance (in shares)		482,000	748,000	1,166,000
Weighted-Average Grant Date Fair Value Per Share (in dollars per share)		$ 397.77	$ 275.7	$ 222.78
Granted (in shares)	[1]	369,000	281,000	35,000	[2]
Weighted-Average Grant Date Fair Value Per Share, granted (in dollars per share)		$ 578.36	$ 449.38	$ 385.8
Vested (in shares)		(169,000)	(543,000)	(452,000)
Weighted-Average Grant Date Fair Value Per Share, vested (in dollars per share)		$ 282.62	$ 257.24	$ 147.78
Forfeited (in shares)		(1,000)	(4,000)	(1,000)
Weighted-Average Grant Date Fair Value Per Share, forfeited (in dollars per share)		$ 409.27	$ 315.19	$ 377.86
Balance (in shares)		681,000	482,000	748,000
Weighted-Average Grant Date Fair Value Per Share (in dollars per share)		$ 524.08	$ 397.77	$ 275.7
MSUs [Member]
Balance (in shares)		1,502,000	1,805,000	1,218,000
Weighted-Average Grant Date Fair Value Per Share (in dollars per share)		$ 152.89	$ 126.57	$ 44.59
Granted (in shares)		0	31,000	917,000
Weighted-Average Grant Date Fair Value Per Share, granted (in dollars per share)		$ 0	$ 330.95	$ 199.63
Vested (in shares)		(563,000)	(319,000)	(324,000)
Weighted-Average Grant Date Fair Value Per Share, vested (in dollars per share)		$ 68.48	$ 23.57	$ 23.57
Forfeited (in shares)		(1,000)	(15,000)	(6,000)
Weighted-Average Grant Date Fair Value Per Share, forfeited (in dollars per share)		$ 270.15	$ 110.65	$ 216.37
Balance (in shares)		938,000	1,502,000	1,805,000
Weighted-Average Grant Date Fair Value Per Share (in dollars per share)		$ 203.32	$ 152.89	$ 126.57

[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.

[2] Amount included grants and cancellations of the 2022 Executive PSUs as defined under the "2022 PSUs" section.