Earnings Per Common Share - Weighted Average Shares (Details) - shares	12 Months Ended
	Jul. 31, 2018	Jul. 31, 2017	Jul. 31, 2016
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)	41,635,078	41,542,765	41,390,194
Participating securities (in shares)	148,700	254,727	340,363
Total weighted average number of shares and common stock equivalents attributable to both common stock and participating securities (shares)	41,783,778	41,797,492	41,730,557