CONDENSED CONSOLIDATED STATEMENT OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands		Total		Total United Natural Foods, Inc. Stockholders’ Equity	Common Stock	Treasury Stock	Additional Paid-in Capital	Accumulated Other Comprehensive (Loss) Income	Retained Earnings	Noncontrolling Interests
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of change in accounting principle		$ 509					$ 1,314		$ (805)
Beginning Balance (shares) at Jul. 29, 2017					50,622,000	0
Beginning Balance at Jul. 29, 2017		1,681,921			$ 506	$ 0	460,011	$ (13,963)	1,235,367
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock option exercises and restricted stock vestings, net of tax (in shares)					350,000
Restricted Stock vestings and stock option exercises, net of tax		(4,156)			$ 4		(4,160)
Share-based compensation		13,846					13,846
Repurchase of common stock						565,000
Repurchase of common stock		(22,237)				$ (22,237)
Other/share-based compensation		107
Fair value of swap agreements, net of tax		2,920						2,920
Foreign currency translation		839						839
Net (loss) income		80,991							80,991
Ending Balance (shares) at Jan. 27, 2018					50,972,000	565,000
Ending Balance at Jan. 27, 2018		1,754,740			$ 510	$ (22,237)	471,118	(10,204)	1,315,553
Beginning Balance (shares) at Jul. 29, 2017					50,622,000	0
Beginning Balance at Jul. 29, 2017		1,681,921			$ 506	$ 0	460,011	(13,963)	1,235,367
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Fair value of swap agreements, net of tax	[1]	3,649
Foreign currency translation		(2,320)
Net (loss) income		132,882
Ending Balance (shares) at Apr. 28, 2018					51,006,000	565,000
Ending Balance at Apr. 28, 2018		1,812,303			$ 510	$ (22,237)	479,220	(12,634)	1,367,444
Beginning Balance (shares) at Jul. 29, 2017					50,622,000	0
Beginning Balance at Jul. 29, 2017		$ 1,681,921			$ 506	$ 0	460,011	(13,963)	1,235,367
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Repurchase of common stock		614,660
Repurchase of common stock		$ (24,200)
Ending Balance (shares) at Jul. 28, 2018		50,411,000			51,025,000	615,000
Ending Balance at Jul. 28, 2018		$ 1,845,955		$ 1,845,955	$ 510	$ (24,231)	483,623	(14,179)	1,400,232	$ 0
Beginning Balance (shares) at Jan. 27, 2018					50,972,000	565,000
Beginning Balance at Jan. 27, 2018		1,754,740			$ 510	$ (22,237)	471,118	(10,204)	1,315,553
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock option exercises and restricted stock vestings, net of tax (in shares)					34,000
Restricted Stock vestings and stock option exercises, net of tax		236			$ 0		236
Share-based compensation		7,866					7,866
Fair value of swap agreements, net of tax		729	[1]					729
Foreign currency translation		(3,159)						(3,159)
Net (loss) income		51,891
Ending Balance (shares) at Apr. 28, 2018					51,006,000	565,000
Ending Balance at Apr. 28, 2018		1,812,303			$ 510	$ (22,237)	479,220	(12,634)	1,367,444
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of change in accounting principle		$ 277		277					277
Stock Issued During Period, Shares, Share-based Compensation, Gross					408,000
Beginning Balance (shares) at Jul. 28, 2018		50,411,000			51,025,000	615,000
Beginning Balance at Jul. 28, 2018		$ 1,845,955		1,845,955	$ 510	$ (24,231)	483,623	(14,179)	1,400,232	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock option exercises and restricted stock vestings, net of tax		(3,019)		3,019	$ (4)		3,023
Share-based compensation		14,511		14,511			14,511
Other/share-based compensation		403		403			403
Fair value of swap agreements, net of tax		(10,702)		(10,702)				(10,702)
Foreign currency translation		(982)		(982)				(982)
Acquisition of noncontrolling interests		(1,633)								1,633
Distributions to noncontrolling interests		(255)								255
Net (loss) income		(361,187)		(361,019)					(361,019)	(168)
Ending Balance (shares) at Jan. 26, 2019					51,433,000	615,000
Ending Balance at Jan. 26, 2019		$ 1,483,368		1,485,424	$ 514	$ (24,231)	495,514	(25,863)	1,039,490	(2,056)
Beginning Balance (shares) at Jul. 28, 2018		50,411,000			51,025,000	615,000
Beginning Balance at Jul. 28, 2018		$ 1,845,955		1,845,955	$ 510	$ (24,231)	483,623	(14,179)	1,400,232	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Fair value of swap agreements, net of tax	[1]	(26,898)
Foreign currency translation		(2,308)
Net (loss) income		$ (304,043)
Ending Balance (shares) at Apr. 27, 2019		51,104,000			51,719,000	615,000
Ending Balance at Apr. 27, 2019		$ 1,530,212		1,532,216	$ 517	$ (24,231)	502,733	(43,385)	1,096,582	(2,004)
Stock Issued During Period, Shares, Share-based Compensation, Gross					26,000
Beginning Balance (shares) at Jan. 26, 2019					51,433,000	615,000
Beginning Balance at Jan. 26, 2019		$ 1,483,368		1,485,424	$ 514	$ (24,231)	495,514	(25,863)	1,039,490	(2,056)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock option exercises and restricted stock vestings, net of tax (in shares)		259,866			260,000
Restricted Stock vestings and stock option exercises, net of tax		$ 3,100
Stock option exercises and restricted stock vestings, net of tax		(115)		115	$ 0		115
Share-based compensation		4,316		4,316			4,316
Fair value of swap agreements, net of tax		(16,196)	[1]	(16,196)				(16,196)
Foreign currency translation		(1,326)		(1,326)				(1,326)
Net (loss) income		$ 57,144		57,092						52
Ending Balance (shares) at Apr. 27, 2019		51,104,000			51,719,000	615,000
Ending Balance at Apr. 27, 2019		$ 1,530,212		1,532,216	$ 517	$ (24,231)	502,733	$ (43,385)	$ 1,096,582	$ (2,004)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Proceeds from Issuance of Common Stock		$ 3,021		$ 3,021	$ 3		$ 3,018

[1] Amounts are net of tax (benefit) expense of $(6.0) million and $0.3 million for the 13-week periods ended April 27, 2019 and April 28, 2018, respectively, and $(9.9) million and $1.6 million for the 39-week periods ended April 27, 2019 and April 28, 2018, respectively.