Central Garden & Pet Company Annual report pursuant to Section 13 and 15(d)

Fair Value Measurements - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Sep. 24, 2016	Sep. 30, 2017	Sep. 24, 2016	Sep. 26, 2015	Nov. 30, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Indefinite-lived intangible assets, impairment charge	$ 1,800	$ 0	$ 1,800	$ 7,300
Indefinite-lived intangible assets, carrying value	1,800		1,800
Carrying value of senior subordinated notes	395,269	395,653	395,269
Senior notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying value of senior subordinated notes	394,365	395,160	394,365
6.125% Senior Notes Due in November 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying value of senior subordinated notes					$ 400,000
Debt instrument interest rate stated, percentage					6.125%
6.125% Senior Notes Due in November 2023 \| Senior notes \| Estimate of Fair Value Measurement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated fair value of senior subordinated notes due 2018	430,300	427,900	430,300
6.125% Senior Notes Due in November 2023 \| Senior notes \| Carrying (Reported) Amount, Fair Value Disclosure
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying value of senior subordinated notes	$ 394,400	$ 395,200	$ 394,400