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 Additional Retained Earnings Treasury Accumulated Other 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 Additional Retained Earnings Treasury Accumulated Other 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 Additional Retained Earnings Treasury Accumulated Other 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 Additional Retained Earnings Treasury Accumulated Other 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 |