Stock-Based Compensation - Stock Options (Details) - USD ($)		3 Months Ended		15 Months Ended
	Oct. 31, 2018	Oct. 31, 2018	Oct. 31, 2017	Oct. 31, 2018
Additional Disclosures
Stock Issued During The Period, Shares, Net Settlement Of Stock-Based Awards		9,345
Stock Options
Awards (in Shares)
Outstanding, Beginning Balance (in shares)		1,668,975
Exercised (in shares)		(78,930)	0
Outstanding, Ending Balance (in shares)	1,590,045	1,590,045		1,590,045
Exercisable (in shares)	1,388,123	1,388,123		1,388,123
Vested and Expected to Vest, Ending Balance (in shares)	1,555,133	1,555,133		1,555,133
Weighted Average Exercise Price
Outstanding, Beginning Balance (in dollars per share)		$ 28.72
Exercised (in dollars per share)		28.37
Outstanding, Ending Balance (in dollars per share)	$ 28.74	28.74		$ 28.74
Exercisable, Ending Balance (in dollars per share)	28.74	28.74		28.74
Vested and Expected to Vest, Ending Balance (in dollars per share)	$ 28.73	$ 28.73		$ 28.73
Weighted Average Remaining Contractual Term (Years)
Outstanding, Ending Balance		4 years 3 months 7 days
Exercisable, Ending Balance		3 years 11 months 10 days
Vested And Expected To Vest, Ending Balance		4 years 2 months 20 days
Aggregate Intrinsic Value
Outstanding, Ending Balance	$ 741,000	$ 741,000		$ 741,000
Exercisable, Ending Balance	574,000	574,000		574,000
Vested and Expected to Vest, Ending Balance	$ 712,000	712,000		$ 712,000
Additional Disclosures
Exercise price, lower range limit (in dollars per share)	$ 20.90
Exercise price, upper range limit (in dollars per share)	$ 33.94
Granted (in shares)			0	0
Total intrinsic value of stock-based awards settled		$ 561,000
Vested stock based awards net settled upon exercise (in shares)		72,830
Minimum | Stock Options
Additional Disclosures
Contractual term (in years)	5 years
Vesting period (in years)	3 years
Maximum | Stock Options
Additional Disclosures
Contractual term (in years)	10 years
Vesting period (in years)	5 years