CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid-In Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Retained Earnings [Member]	Total	Cumulative Effect, Period of Adoption, Adjustment [Member] Common Stock [Member]	Cumulative Effect, Period of Adoption, Adjustment [Member] Additional Paid-In Capital [Member]	Cumulative Effect, Period of Adoption, Adjustment [Member] Accumulated Other Comprehensive Income (Loss) [Member]	Cumulative Effect, Period of Adoption, Adjustment [Member] Retained Earnings [Member]	Cumulative Effect, Period of Adoption, Adjustment [Member]
Balance at Jul. 28, 2017	$ 241	$ 55,659	$ (4,229)	$ 492,836	$ 544,507
Balance (in shares) at Jul. 28, 2017	24,055,682
Comprehensive Income:
Net income (loss)	$ 0	0	0	247,620	247,620
Other comprehensive income (loss), net of tax	0	0	8,914	0	8,914
Comprehensive income (loss)	0	0	8,914	247,620	256,534
Cash dividends declared	0	0	0	(207,649)	(207,649)
Share-based compensation	0	6,977	0	0	6,977
Issuance of share-based compensation awards, net of shares withheld for employee taxes	$ 0	(3,816)	0	0	(3,816)
Issuance of share-based compensation awards, net of shares withheld for employee taxes (in shares)	55,868
Purchases and retirement of common stock	$ (1)	(14,771)	0	0	(14,772)
Purchases and retirement of common stock (in shares)	(100,000)
Balance at Aug. 03, 2018	$ 240	44,049	4,685	532,807	581,781
Balance (in shares) at Aug. 03, 2018	24,011,550
Comprehensive Income:
Net income (loss)	$ 0	0	0	223,401	223,401
Other comprehensive income (loss), net of tax	0	0	(11,598)	0	(11,598)
Comprehensive income (loss)	0	0	(11,598)	223,401	211,803
Cash dividends declared	0	0	0	(194,558)	(194,558)
Share-based compensation	0	8,181	0	0	8,181
Issuance of share-based compensation awards, net of shares withheld for employee taxes	$ 1	(2,498)	0	0	(2,497)
Issuance of share-based compensation awards, net of shares withheld for employee taxes (in shares)	37,690
Purchases and retirement of common stock	$ 0	0	0	0	0
Purchases and retirement of common stock (in shares)	0
Balance at Aug. 02, 2019	$ 241	49,732	(6,913)	561,650	$ 604,710
Balance (Adjustments for New Accounting Pronouncement [Member]) at Aug. 02, 2019						$ 0	$ 0	$ 0	$ 4,125	$ 4,125
Balance (in shares) at Aug. 02, 2019	24,049,240				24,049,240
Comprehensive Income:
Net income (loss)	$ 0	0	0	(32,475)	$ (32,475)
Other comprehensive income (loss), net of tax	0	0	(13,433)	0	(13,433)
Comprehensive income (loss)	0	0	(13,433)	(32,475)	(45,908)
Cash dividends declared	0	0	0	(93,757)	(93,757)
Share-based compensation	0	6,386	0	0	6,386
Issuance of share-based compensation awards, net of shares withheld for employee taxes	$ 0	(2,160)	0	0	$ (2,160)
Issuance of share-based compensation awards, net of shares withheld for employee taxes (in shares)	27,130				27,130
Purchases and retirement of common stock	$ (4)	(53,958)	0	(1,045)	$ (55,007)
Purchases and retirement of common stock (in shares)	(378,974)
Balance at Jul. 31, 2020	$ 237	$ 0	$ (20,346)	$ 438,498	$ 418,389
Balance (in shares) at Jul. 31, 2020	23,697,396				23,697,396