Earnings per share (Schedule of Calculation of Basic and Diluted Earnings Per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Feb. 28, 2023	Feb. 28, 2022
Earnings Per Share [Abstract]
Net income	$ 23,674	$ 20,454
Weighted average shares outstanding (in shares)	43,300	43,981
Basic earnings per common share (in dollars per share)	$ 0.55	$ 0.47
Diluted earnings per common share:
Net income	$ 23,674	$ 20,454
Effect of dilution from common stock equivalents (in shares)	1,053	727
Diluted weighted average shares outstanding (in shares)	44,353	44,708
Diluted earnings per share (in dollars shares)	$ 0.53	$ 0.46