Earnings Per Share - Earnings Per Share, Basic and Diluted (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 26, 2016	Mar. 28, 2015	Mar. 26, 2016	Mar. 28, 2015
Basic EPS:
Net income attributable to Central Garden & Pet Company	$ 32,697	$ 23,237	$ 24,095	$ 17,540
Weighted average shares, basic	48,717	48,384	48,641	48,882
Earnings per share, basic (in dollars per share)	$ 0.67	$ 0.48	$ 0.50	$ 0.36
Earnings Per Share, Diluted [Abstract]
Net income available to common shareholders	$ 32,697	$ 23,237	$ 24,095	$ 17,540
Weighted average shares, diluted	50,445	49,439	50,558	49,689
Earnings per share, diluted (in dollars per share)	$ 0.65	$ 0.47	$ 0.48	$ 0.35
Options to purchase common stock
Effect of dilutive securities:
Effective of dilutive securities, in shares	976	457	1,166	251
Effect of dilutive securities (in dollars per share)	$ (0.01)	$ 0.00	$ (0.02)	$ 0.00
Restricted shares
Effect of dilutive securities:
Effective of dilutive securities, in shares	752	598	751	556
Effect of dilutive securities (in dollars per share)	$ (0.01)	$ (0.01)	$ 0.00	$ (0.01)