Net Income Per Common Share Net Income per Common Share (Narrative) (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended		9 Months Ended
	Jun. 07, 2017	Apr. 30, 2017	Apr. 30, 2016	Apr. 30, 2017	Apr. 30, 2016
Anti-dilutive securities (in shares)		12,000	24,000	4,000	13,000
Cash dividends declared per share		$ 1.053	$ 0.81	$ 2.673	$ 2.055
Payments of Dividends		$ 42,300	$ 29,300	$ 104,035	$ 74,530
Dividends Payable, Date to be Paid		Jul. 13, 2017
Dividends Payable, Date of Record		Jun. 28, 2017
Scenario, Forecast [Member]
Cash dividends declared per share	$ 1.053
Common Stock [Member]
Stock Issued During Period, Shares, New Issues				3,327,719
Exchangeable Shares [Member]
Stock Issued During Period, Shares, New Issues				418,095