Earnings Per Common Share - Weighted Average Shares (Details) - shares	12 Months Ended
	Jul. 31, 2017	Jul. 31, 2016	Jul. 31, 2015
Reconciliation of weighted average number of shares and common stock equivalents attributable to common stock, to the entity's total weighted average number of shares and common stock equivalents, including participating securities
Denominator for diluted earnings per share - weighted average number of shares and common stock equivalents attributable to common stock (shares)	41,542,765	41,390,194	41,202,600
Participating securities (in shares)	254,727	340,363	378,706
Total weighted average number of shares and common stock equivalents attributable to both common stock and participating securities (shares)	41,797,492	41,730,557	41,581,306