Stockholders' Equity - Stock Repurchases, Cash Dividend (Details) - USD ($)		3 Months Ended		9 Months Ended
	May 10, 2017	Feb. 28, 2018	Feb. 28, 2017	Aug. 31, 2018	Aug. 31, 2017	May 11, 2016
Stock Repurchases
Stock repurchased					$ 1,474,000
Cash Dividend
Cash dividend paid		$ 2,000,000	$ 1,514,000	$ 2,000,000	$ 1,514,000
Cash dividends declared (in dollars per share)				$ 0	$ 0
Stock Repurchases
Stock Repurchases
Stock repurchase program, authorized amount						$ 5,000,000
Stock repurchased (in shares)	152,173				47,173
Stock repurchased	$ 4,828				$ 1,474,000