Stock-Based Compensation (Performance Shares, RSUs, Restricted Stock and Share Unit Awards) (Details)		3 Months Ended			6 Months Ended		12 Months Ended
	Jul. 31, 2017	Jan. 31, 2021 USD ($) $ / shares shares	Oct. 31, 2020 $ / shares shares	Jan. 31, 2020 USD ($)	Jan. 31, 2021 USD ($) $ / shares shares	Jan. 31, 2020 USD ($)	Jul. 31, 2019	Jul. 31, 2020 USD ($)
Dividend Equivalents [Abstract]
Accrued during the period		$ 49,000		$ 57,000	$ 191,000	$ 113,000
Carrying value at period end		483,311,000			483,311,000			$ 380,348,000
Income tax (expense) benefit from settlement of stock-based awards		$ (8,000)		(141,000)	$ (207,000)	471,000
Performance Shares, RSUs, Restricted Stock and Share Units
Awards (In Shares)
Outstanding, Beginning Balance (in shares) | shares		1,141,645	999,574		999,574
Granted (in shares) | shares			383,337
Settled (in shares) | shares		(526)	(176,051)
Forfeited (in shares) | shares		(7,229)	(65,215)
Outstanding, Ending Balance (in shares) | shares		1,133,890	1,141,645		1,133,890
Vested, Ending Balance (in shares) | shares		396,254			396,254
Vested and Expected to Vest, Ending Balance (in shares) | shares		1,085,777			1,085,777
Weighted Average Grant Date Fair Value
Outstanding, Beginning Balance (in dollars per share) | $ / shares		$ 20.03	$ 21.15		$ 21.15
Granted (in dollars per share) | $ / shares			16.67
Settled (in dollars per share) | $ / shares		11.40	20.47
Forfeited (in dollars per share) | $ / shares		20.15	16.16
Outstanding, Ending Balance (in dollars per share) | $ / shares		20.04	$ 20.03		20.04
Vested, Ending Balance (in dollars per share) | $ / shares		16.61			16.61
Vested and Expected to Vest, Ending Balance (in dollars per share) | $ / shares		$ 19.98			$ 19.98
Aggregate Intrinsic Value
Outstanding, Ending Balance		$ 24,197,000			$ 24,197,000
Vested, Ending Balance					8,456,000
Vested and Expected to Vest, Ending Balance		23,170,000			23,170,000
Additional Disclosures
Total intrinsic value relating to fully vested stock-based awards converted during the period		$ 9,000		$ 19,000	$ 2,905,000	$ 5,825,000
Performance shares | Employees | Granted since fiscal 2014
Additional Disclosures
Performance period (in years)					3 years
RSUs and restricted stock | Employees
Additional Disclosures
Vesting period (in years)					5 years
Common stock, conversion ratio (in shares)		1			1
RSUs and restricted stock | Non-Employee Director
Additional Disclosures
Vesting period (in years)					5 years		3 years
Common stock, conversion ratio (in shares)							1
Share units
Additional Disclosures
Common stock, conversion ratio (in shares)	1
Conversion period of vested share units	1 year
Number of units settled to date (in shares) | shares		672,085			672,085
Dividend equivalents
Dividend Equivalents [Abstract]
Accrued during the period		$ 49,000			$ 191,000
Paid during the period		1,000			276,000
Carrying value at period end		$ 698,000			$ 698,000			$ 783,000