Consolidating Condensed Financial Information of Guarantor Subsidiaries - Consolidating Condensed Statement of Operations (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 24, 2016	Jun. 25, 2016	Mar. 26, 2016	Dec. 26, 2015	Sep. 26, 2015	Jun. 27, 2015	Mar. 28, 2015	Dec. 27, 2014	Sep. 24, 2016	Sep. 26, 2015	Sep. 27, 2014
Condensed Financial Statements, Captions [Line Items]
Net sales	$ 413,412	$ 514,544	$ 541,249	$ 359,812	$ 386,369	$ 459,446	$ 497,602	$ 307,320	$ 1,829,017	$ 1,650,737	$ 1,604,357
Cost of goods sold and occupancy									1,275,967	1,162,685	1,150,333
Gross profit	120,180	163,745	169,339	99,786	107,972	142,037	150,062	87,981	553,050	488,052	454,024
Selling, general and administrative expenses									423,692	396,617	397,811
Operating income									129,358	91,435	56,213
Interest expense									(42,847)	(40,027)	(42,844)
Interest income									140	129	94
Other income (expense)									(17,013)	13	403
Income (loss) before taxes and equity in earnings of affiliates									69,638	51,550	13,866
Income tax expense									24,053	18,535	4,045
Equity in earnings of affiliates									0	0	0
Net income including noncontrolling interest									45,585	33,015	9,821
Noncontrolling interest									1,071	1,044	1,017
Net income attributable to Central Garden & Pet Company	$ (5,611)	$ 26,030	$ 32,697	$ (8,602)	$ (4,369)	$ 18,800	$ 23,237	$ (5,697)	44,514	31,971	8,804
Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Net sales									(79,468)	(80,521)	(69,803)
Cost of goods sold and occupancy									(73,876)	(74,944)	(64,404)
Gross profit									(5,592)	(5,577)	(5,399)
Selling, general and administrative expenses									(5,592)	(5,577)	(5,399)
Operating income									0	0	0
Interest expense									0	0	0
Interest income									0	0	0
Other income (expense)									0	0	0
Income (loss) before taxes and equity in earnings of affiliates									0	0	0
Income tax expense									0	0	0
Equity in earnings of affiliates									(95,725)	(72,593)	(52,763)
Net income including noncontrolling interest									(95,725)	(72,593)	(52,763)
Noncontrolling interest									0	0	0
Net income attributable to Central Garden & Pet Company									(95,725)	(72,593)	(52,763)
Parent [Member]
Condensed Financial Statements, Captions [Line Items]
Net sales									587,579	484,310	460,781
Cost of goods sold and occupancy									466,543	379,235	370,492
Gross profit									121,036	105,075	90,289
Selling, general and administrative expenses									138,556	124,613	117,240
Operating income									(17,520)	(19,538)	(26,951)
Interest expense									(42,700)	(39,893)	(42,742)
Interest income									136	126	92
Other income (expense)									(16,925)	(372)	186
Income (loss) before taxes and equity in earnings of affiliates									(77,009)	(59,677)	(69,415)
Income tax expense									(26,422)	(21,500)	(26,962)
Equity in earnings of affiliates									95,101	70,148	51,257
Net income including noncontrolling interest									44,514	31,971	8,804
Noncontrolling interest									0	0	0
Net income attributable to Central Garden & Pet Company									44,514	31,971	8,804
Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net sales									82,567	100,127	109,453
Cost of goods sold and occupancy									62,727	76,597	87,028
Gross profit									19,840	23,530	22,425
Selling, general and administrative expenses									18,077	18,329	18,230
Operating income									1,763	5,201	4,195
Interest expense									(266)	(268)	(218)
Interest income									4	3	2
Other income (expense)									(113)	407	583
Income (loss) before taxes and equity in earnings of affiliates									1,388	5,343	4,562
Income tax expense									923	2,089	756
Equity in earnings of affiliates									0	0	0
Net income including noncontrolling interest									465	3,254	3,806
Noncontrolling interest									1,071	1,044	1,017
Net income attributable to Central Garden & Pet Company									(606)	2,210	2,789
Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net sales									1,238,339	1,146,821	1,103,926
Cost of goods sold and occupancy									820,573	781,797	757,217
Gross profit									417,766	365,024	346,709
Selling, general and administrative expenses									272,651	259,252	267,740
Operating income									145,115	105,772	78,969
Interest expense									119	134	116
Interest income									0	0	0
Other income (expense)									25	(22)	(366)
Income (loss) before taxes and equity in earnings of affiliates									145,259	105,884	78,719
Income tax expense									49,552	37,946	30,251
Equity in earnings of affiliates									624	2,445	1,506
Net income including noncontrolling interest									96,331	70,383	49,974
Noncontrolling interest									0	0	0
Net income attributable to Central Garden & Pet Company									$ 96,331	$ 70,383	$ 49,974