Quarterly Financial Data (Unaudited) - Quarterly Results of Operations (Detail) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Oct. 31, 2016	Jul. 31, 2016	Apr. 30, 2016	Jan. 31, 2016	Oct. 31, 2015	Jul. 31, 2015	Apr. 30, 2015	Jan. 31, 2015	Oct. 31, 2016	Oct. 31, 2015	Oct. 31, 2014
Quarterly Results Of Operations [Line Items]
Net sales	$ 867.6	$ 845.0	$ 839.6	$ 771.4	$ 868.5	$ 930.0	$ 915.9	$ 902.3	$ 3,323.6	$ 3,616.7	$ 4,239.1
Gross profit	183.4	176.5	173.7	151.3	168.0	166.8	181.1	153.9	684.9	669.8	811.0
Net income (loss)	6.5	46.4	32.5	(9.9)	9.2	9.3	20.5	28.2	75.5	67.2	44.9
Net income attributable to Greif, Inc.	8.5	$ 46.1	$ 31.4	$ (11.1)	12.4	$ 8.6	$ 20.8	$ 30.1	74.9	71.9	91.5
Diluted:
Restructuring charges	9.0				13.3				26.9	40.0	16.1
Asset impairment charges	6.5				23.6				51.4	45.9	85.8
Gain (loss) on disposals of properties, plants and equipment, net	0.8				(2.3)				10.3	7.0	8.3
Gain (loss) on disposal of businesses, net	$ (18.6)				$ (0.7)				$ (14.5)	$ (9.2)	$ 11.5
Class A Common Stock
Basic earnings per share attributable to Greif, Inc.:
EPS Basic (usd per share)	$ 0.14	$ 0.78	$ 0.53	$ (0.19)	$ 0.21	$ 0.15	$ 0.35	$ 0.52	$ 1.28	$ 1.23	$ 1.56
Diluted earnings per share attributed to Greif, Inc.:
EPS Diluted (usd per share)	$ 0.14	$ 0.78	$ 0.53	$ (0.19)	$ 0.21	$ 0.15	$ 0.35	$ 0.52	$ 1.28	$ 1.23	$ 1.56
Basic:
Basic (shares)	25,781,791	25,781,146	25,761,733	25,697,512	25,693,564	25,692,973	25,678,393	25,607,886	25,755,545	25,668,204	25,547,650
Diluted:
Diluted (shares)	25,785,266	25,783,184	25,766,609	25,704,023	25,701,264	25,698,547	25,688,653	25,617,814	25,756,893	25,674,105	25,552,986
Market price of common stock (usd per share)	$ 46.86	$ 39.77	$ 34.02	$ 25.51	$ 32.33	$ 30.20	$ 39.29	$ 36.43
Class B Common Stock
Basic earnings per share attributable to Greif, Inc.:
EPS Basic (usd per share)	0.22	1.18	0.80	(0.29)	0.32	0.22	0.53	0.76	$ 1.90	$ 1.83	$ 2.33
Diluted earnings per share attributed to Greif, Inc.:
EPS Diluted (usd per share)	$ 0.22	$ 1.18	$ 0.80	$ (0.29)	$ 0.32	$ 0.22	$ 0.53	$ 0.76	$ 1.90	$ 1.83	$ 2.33
Basic:
Basic (shares)	22,009,725	22,009,725	22,108,942	22,119,966	22,119,966	22,119,966	22,119,966	22,119,966	22,100,000	22,100,000	22,100,000
Diluted:
Diluted (shares)	22,009,725	22,009,725	22,108,942	22,119,966	22,119,966	22,119,966	22,119,966	22,119,966	22,100,000	22,100,000	22,100,000
Market price of common stock (usd per share)	$ 58.25	$ 52.41	$ 45.07	$ 35.11	$ 37.98	$ 37.13	$ 45.89	$ 41.47
Maximum | Class A Common Stock
Diluted:
Market price of common stock (usd per share)	49.59	40.09	35.56	33.77	35.97	41.65	41.97	45.94
Maximum | Class B Common Stock
Diluted:
Market price of common stock (usd per share)	60.98	55.48	47.38	45.80	47.97	47.80	45.89	47.39
Minimum | Class A Common Stock
Diluted:
Market price of common stock (usd per share)	38.92	32.96	23.17	24.05	27.13	29.43	34.52	36.43
Minimum | Class B Common Stock
Diluted:
Market price of common stock (usd per share)	$ 50.26	$ 44.38	$ 32.91	$ 34.48	$ 33.42	$ 36.59	$ 40.40	$ 41.47