Consolidating Condensed Financial Information of Guarantor Subsidiaries - Consolidating Condensed Statements of Comprehensive Income (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 24, 2016	Sep. 26, 2015	Sep. 27, 2014
Condensed Financial Statements, Captions [Line Items]
Net income	$ 45,585	$ 33,015	$ 9,821
Other comprehensive income (loss):
Unrealized loss on securities	0	(10)	(10)
Reclassification of realized loss on securities included in net income	0	20	0
Foreign currency translation	(1,458)	(1,078)	(200)
Total comprehensive income	44,127	31,947	9,611
Comprehensive income attributable to noncontrolling interests	1,071	1,044	1,017
Comprehensive income attributable to Central Garden & Pet Company	43,056	30,903	8,594
Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Net income	(95,725)	(72,593)	(52,763)
Other comprehensive income (loss):
Unrealized loss on securities			0
Reclassification of realized loss on securities included in net income		0
Foreign currency translation	1,124	917	0
Total comprehensive income	(94,601)	(71,676)	(52,763)
Comprehensive income attributable to noncontrolling interests	0	0	0
Comprehensive income attributable to Central Garden & Pet Company	(94,601)	(71,676)	(52,763)
Parent [Member]
Condensed Financial Statements, Captions [Line Items]
Net income	44,514	31,971	8,804
Other comprehensive income (loss):
Unrealized loss on securities		(10)	(10)
Reclassification of realized loss on securities included in net income		20
Foreign currency translation	(1,458)	(1,078)	0
Total comprehensive income	43,056	30,903	8,794
Comprehensive income attributable to noncontrolling interests	0	0	0
Comprehensive income attributable to Central Garden & Pet Company	43,056	30,903	8,794
Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net income	465	3,254	3,806
Other comprehensive income (loss):
Unrealized loss on securities		0	0
Reclassification of realized loss on securities included in net income		0
Foreign currency translation	(1,132)	(537)	(200)
Total comprehensive income	(667)	2,717	3,606
Comprehensive income attributable to noncontrolling interests	1,071	1,044	1,017
Comprehensive income attributable to Central Garden & Pet Company	(1,738)	1,673	2,589
Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net income	96,331	70,383	49,974
Other comprehensive income (loss):
Unrealized loss on securities			0
Reclassification of realized loss on securities included in net income		0
Foreign currency translation	8	(380)	0
Total comprehensive income	96,339	70,003	49,974
Comprehensive income attributable to noncontrolling interests	0	0	0
Comprehensive income attributable to Central Garden & Pet Company	$ 96,339	$ 70,003	$ 49,974