Quarterly Results (unaudited) - Summary of Quarterly Results (Details) - USD ($)	3 Months Ended								12 Months Ended
	Apr. 28, 2018	Jan. 27, 2018	Oct. 28, 2017	Jul. 29, 2017	Apr. 29, 2017	Jan. 28, 2017	Oct. 29, 2016	Jul. 30, 2016	Apr. 27, 2019	Apr. 28, 2018	Apr. 29, 2017	Jul. 28, 2018
Quarterly Financial Information Disclosure [Abstract]
Net sales	$ 1,436,706,000	$ 1,396,745,000	$ 1,404,752,000	$ 1,336,320,000	$ 1,400,609,000	$ 1,375,222,000	$ 1,385,737,000	$ 1,304,115,000	$ 5,574,523,000	$ 5,465,683,000	$ 5,593,127,000
Gross profit	312,527,000	299,509,000	295,076,000	283,663,000	289,839,000	294,736,000	315,743,000	299,048,000	1,190,775,000	1,199,366,000	1,301,397,000
Operating income from continuing operations	46,623,000	45,363,000	41,216,000	4,514,000	41,251,000	50,046,000	71,759,000	56,833,000	137,716,000	219,889,000	287,928,000
Net income from continuing operations	27,685,000	31,054,000	28,646,000	(4,509,000)	20,928,000	108,955,000	40,244,000	30,847,000	82,876,000	200,974,000	173,788,000
Net income from discontinued operations	0	0	0	0	0	0	0	0
Net income (loss)	27,685,000	31,054,000	28,646,000	(4,509,000)	20,928,000	108,955,000	40,244,000	30,847,000	82,876,000	200,974,000	170,893,000
Net loss attributable to noncontrolling interests	(305,000)	(171,000)	(223,000)	(53,000)	0	0	0	0	(752,000)	0	0
Net income attributable to Patterson Companies, Inc.	$ 27,990,000	$ 31,225,000	$ 28,869,000	$ (4,456,000)	$ 20,928,000	$ 108,955,000	$ 40,244,000	$ 30,847,000	$ 83,628,000	$ 200,974,000	$ 170,893,000
Basic earnings (loss) per share attributable to Patterson Companies, Inc.:
Continuing operations (in usd per share)	$ 0.30	$ 0.34	$ 0.31	$ (0.05)	$ 0.23	$ 1.18	$ 0.43	$ 0.33	$ 0.90	$ 2.17	$ 1.83
Discontinued operations (in usd per share)	0	0	0	0	0	0	0	0	0	0	(0.03)
Basic (in usd per share)	0.30	0.34	0.31	(0.05)	0.23	1.18	0.43	0.33	0.90	2.17	1.80
Diluted earnings (loss) per share attributable to Patterson Companies, Inc.:
Continuing operations (in usd per share)	0.30	0.33	0.31	(0.05)	0.23	1.18	0.43	0.33	0.89	2.16	1.82
Discontinued operations (in usd per share)	0	0	0	0	0	0	0	0	0	0	(0.03)
Diluted (in usd per share)	$ 0.30	$ 0.33	$ 0.31	$ (0.05)	$ 0.23	$ 1.18	$ 0.43	$ 0.33	$ 0.89	$ 2.16	$ 1.79
Tax Cuts And Jobs Act Of 2017, provisional income tax benefit		$ 77,256								$ (76,648,000)
Litigation settlement reserve												$ 28,263,000