Earnings per share - Calculation of Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Aug. 31, 2022	Aug. 31, 2021	Aug. 31, 2022	Aug. 31, 2021
Earnings Per Share [Abstract]
Net income	$ 21,797	$ 30,976	$ 71,361	$ 63,494
Weighted average shares outstanding (in shares)	43,211	43,762	43,589	43,896
Basic earnings per common share (in dollars per share)	$ 0.50	$ 0.71	$ 1.64	$ 1.45
Diluted earnings per common share:
Net income	$ 21,797	$ 30,976	$ 71,361	$ 63,494
Effect of dilution from common stock equivalents (in shares)	724	740	710	646
Diluted weighted average shares outstanding (in shares)	43,935	44,502	44,299	44,542
Diluted earnings per share (in dollars shares)	$ 0.50	$ 0.70	$ 1.61	$ 1.43