Accumulated Other Comprehensive Income (Loss) (Details) - USD ($)	3 Months Ended
	Oct. 31, 2015	Oct. 31, 2014
Components and changes in accumulated other comprehensive income (loss)
Balance	$ 406,633,000
Other comprehensive loss	(827,000)	$ (1,891,000)
Balance	417,629,000
Accumulated Other Comprehensive Income
Components and changes in accumulated other comprehensive income (loss)
Balance	1,224,000	9,552,000
Other comprehensive loss	(827,000)	(1,891,000)
Balance	$ 397,000	$ 7,661,000