Note 6 - Accounting for Share-based Compensation - Stock Option Activity (Details)	9 Months Ended
	Aug. 31, 2019 $ / shares shares
Outstanding Options (in shares) | shares	4,466,106
Outstanding Options, weighted-average exercise price (in dollars per share) | $ / shares	$ 44.72
Granted (in shares) | shares	962,130
Granted, weighted-average exercise price (in dollars per share) | $ / shares	$ 45.47
Exercised (in shares) | shares	(96,740)
Exercised, weighted-average exercise price (in dollars per share) | $ / shares	$ 25.79
Forfeited or cancelled (in shares) | shares	(30,036)
Forfeited or cancelled, weighted-average exercise price (in dollars per share) | $ / shares	$ 48.73
Outstanding Options (in shares) | shares	5,301,460
Outstanding Options, weighted-average exercise price (in dollars per share) | $ / shares	$ 45.18