Stockholders' Equity Schedule of Stockholders' Equity (Tables)
 3 Months Ended 9 Months Ended
Apr. 30, 2020
Apr. 30, 2019
Apr. 30, 2020
Apr. 30, 2019
Stockholders' Equity Note [Abstract]        
Schedule of Stockholders Equity [Table Text Block]
The following table illustrates the changes in the balances of each component of stockholders' equity for the three months ended April 30, 2020:

Common
Stock		Additional
Paid-In
Capital		Retained EarningsTreasury
Stock		Accumulated Other
Comprehensive Loss		Total Stockholders' Equity
Balances at January 31, 2020$548  $329,263  $685,758  $(43,155) $(72,490) $899,924  
Net income—  —  13,633  —  —  13,633  
Other comprehensive loss, net of tax—  —  —  —  (19,752) (19,752) 
Issuance of shares of Class A Common Stock under stock plan—  (91) —  517  —  426  
Stock-based compensation expense—  1,796  —  —  —  1,796  
Repurchase of shares of Class A Common Stock—  —  —  (64,113) —  (64,113) 
Cash dividends on Common Stock:
Class A — $0.22 per share—  —  (10,542) —  —  (10,542) 
Class B — $0.22 per share—  —  (770) —  —  (770) 
Balances at April 30, 2020$548  $330,968  $688,079  $(106,751) $(92,242) $820,602  
The following table illustrates the changes in the balances of each component of stockholders' equity for the three months ended April 30, 2019:

Common
Stock		Additional
Paid-In
Capital		Retained EarningsTreasury
Stock		Accumulated Other
Comprehensive Loss		Total Stockholders' Equity
Balances at January 31, 2019$548  $328,978  $588,918  $(54,498) $(60,565) $803,381  
Net income—  —  34,781  —  —  34,781  
Other comprehensive loss, net of tax—  —  —  —  (7,881) (7,881) 
Issuance of shares of Class A Common Stock under stock plan—  (1,433) —  4,415  —  2,982  
Stock-based compensation expense—  2,506  —  —  —  2,506  
Cash dividends on Common Stock:
Class A — $0.21 per share—  —  (10,473) —  —  (10,473) 
Class B — $0.21 per share—  —  (752) —  —  (752) 
Balances at April 30, 2019$548  $330,051  $612,474  $(50,083) $(68,446) $824,544  
The following table illustrates the changes in the balances of each component of stockholders' equity for the nine months ended April 30, 2020:

Common
Stock		Additional
Paid-In
Capital		Retained EarningsTreasury
Stock		Accumulated Other
Comprehensive Loss		Total Stockholders' Equity
Balances at July 31, 2019$548  $329,969  $637,843  $(46,332) $(71,254) $850,774  
Net income—  —  84,684  —  —  84,684  
Other comprehensive loss, net of tax—  —  —  —  (20,988) (20,988) 
Issuance of shares of Class A Common Stock under stock plan—  (6,314) —  3,694  —  (2,620) 
Tax benefit and withholdings from deferred compensation distributions—  133  —  —  —  133  
Stock-based compensation expense—  7,180  —  —  —  7,180  
Repurchase of shares of Class A Common Stock—  —  —  (64,113) —  (64,113) 
Cash dividends on Common Stock:
Class A — $0.65 per share—  —  (32,197) —  —  (32,197) 
Class B — $0.64 per share—  —  (2,251) —  —  (2,251) 
Balances at April 30, 2020$548  $330,968  $688,079  $(106,751) $(92,242) $820,602  
The following table illustrates the changes in the balances of each component of stockholders' equity for the nine months ended April 30, 2019:

Common
Stock		Additional
Paid-In
Capital		Retained EarningsTreasury
Stock		Accumulated Other
Comprehensive Loss		Total Stockholders' Equity
Balances at July 31, 2018$548  $325,631  $553,454  $(71,120) $(56,401) $752,112  
Net income—  —  94,645  —  —  94,645  
Other comprehensive loss, net of tax—  —  —  —  (12,045) (12,045) 
Issuance of shares of Class A Common Stock under stock plan—  (6,100) —  24,219  —  18,119  
Tax benefit and withholdings from deferred compensation distributions—  209  —  —  —  209  
Stock-based compensation expense—  10,311  —  —  —  10,311  
Repurchase of shares of Class A Common Stock—  —  —  (3,182) —  (3,182) 
Adoption of ASU 2014-09, "Revenue from Contracts with Customers"—  —  (2,137) —  —  (2,137) 
Cash dividends on Common Stock:
Class A — $0.64 per share—  —  (31,291) —  —  (31,291) 
Class B — $0.62 per share—  —  (2,197) —  —  (2,197) 
Balances at April 30, 2019$548  $330,051  $612,474  $(50,083) $(68,446) $824,544