Segment Information - Financial Information Relating to Company's Business Segments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 27, 2020	Jun. 29, 2019	Jun. 27, 2020	Jun. 29, 2019	Sep. 28, 2019
Net sales:
Net sales	$ 833,483	$ 706,575	$ 2,019,540	$ 1,842,266
Operating Income (loss)
Total operating income	104,640	68,871	172,810	141,205
Interest expense - net	(11,471)	(8,498)	(29,444)	(24,960)
Other income (expense)	(3,541)	180	(4,215)	488
Income tax expense	20,291	14,212	31,211	26,031
Income including noncontrolling interest	69,337	46,341	107,940	90,702
Net income attributable to noncontrolling interest	537	189	853	356
Net income attributable to Central Garden & Pet Company	68,800	46,152	107,087	90,346
Depreciation and amortization:
Depreciation and amortization	13,283	13,082	39,598	37,311
Assets:
Assets	2,263,969	2,064,918	2,263,969	2,064,918	$ 2,025,020
Goodwill (included in corporate assets above):
Goodwill	289,854	281,177	289,854	281,177	286,077
Pet Segment
Net sales:
Net sales	413,260	350,155	1,128,073	1,028,754
Garden Segment
Net sales:
Net sales	420,223	356,420	891,467	813,512
Operating segments | Pet Segment
Operating Income (loss)
Total operating income	50,760	35,066	114,599	91,805
Depreciation and amortization:
Depreciation and amortization	8,374	8,083	25,305	24,178
Assets:
Assets	810,524	742,938	810,524	742,938	734,380
Goodwill (included in corporate assets above):
Goodwill	272,066	268,289	272,066	268,289	268,289
Operating segments | Garden Segment
Operating Income (loss)
Total operating income	77,787	53,103	122,439	101,821
Depreciation and amortization:
Depreciation and amortization	3,538	3,497	10,157	8,635
Assets:
Assets	635,671	558,260	635,671	558,260	463,889
Goodwill (included in corporate assets above):
Goodwill	17,788	12,888	17,788	12,888	17,788
Corporate
Operating Income (loss)
Total operating income	(23,907)	(19,298)	(64,228)	(52,421)
Depreciation and amortization:
Depreciation and amortization	1,371	1,502	4,136	4,498
Assets:
Assets	$ 817,774	$ 763,720	$ 817,774	$ 763,720	$ 826,751