Net Income Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	May 31, 2020	May 31, 2019	May 31, 2020	May 31, 2019
Basic Earnings per Share
Net income	$ 9,908	$ 8,541	$ 25,149	$ 22,637
Less: Allocated to participating securities	86	68	201	177
Available to common shareholders	$ 9,822	$ 8,473	$ 24,948	$ 22,460
Basic weighted average shares outstanding	9,363,559	9,337,436	9,357,176	9,333,098
Net income per share - Basic (in dollars per share)	$ 1.05	$ 0.91	$ 2.67	$ 2.41
Diluted Earnings per Share
Net income	$ 9,908	$ 8,541	$ 25,149	$ 22,637
Less: Allocated to participating securities	86	68	201	177
Net income available to common shareholders	$ 9,822	$ 8,473	$ 24,948	$ 22,460
Basic weighted average shares outstanding	9,363,559	9,337,436	9,357,176	9,333,098
Additional dilutive common stock equivalents (in shares)	65,704	41,474	78,721	44,650
Diluted weighted average shares outstanding	9,429,263	9,378,910	9,435,897	9,377,748
Net income per share - Diluted (in dollars per share)	$ 1.04	$ 0.90	$ 2.64	$ 2.39
Antidilutive securities
Antidilutive stock options excluded from computation of earnings per share amount (in shares)	17,913	15,625	11,841	14,566