Stock Option Plan - Restricted Stock Units Activity (Details) - Restricted Stock Units $ / shares in Units, $ in Millions	6 Months Ended
	Feb. 29, 2020 USD ($) $ / shares shares
Units
Non-vested at beginning of period (in shares) | shares	92,400
Granted (in shares) | shares	132,633
Vested (in shares) | shares	(50,927)
Forfeited (in shares) | shares	(2,284)
Non-vested at end of period (in shares) | shares	171,822
Weighted average grant-date fair value
Non-vested at beginning of period (in dollars per share) | $ / shares	$ 17.50
Granted (in dollars per share) | $ / shares	25.49
Vested (in dollars per share) | $ / shares	18.20
Forfeited (in dollars per share) | $ / shares	15.87
Non-vested at end of period (in dollars per share) | $ / shares	$ 23.49
Additional disclosures
Unrecognized compensation costs | $	$ 3.2
Period for recognition of unrecognized compensation cost	1 year 11 months 15 days