Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 27, 2016	Sep. 29, 2015	Sep. 27, 2016	Sep. 29, 2015
Amounts used for basic and diluted per share calculations
Net income attributable to Panera Bread Company	$ 31,975	$ 32,393	$ 101,564	$ 106,182
Weighted average number of shares outstanding - basic (in shares)	23,276	25,394	23,651	26,011
Effect of dilutive stock-based employee compensation awards (in shares)	115	107	123	108
Weighted average number of shares outstanding - diluted (in shares)	23,391	25,501	23,774	26,119
Earnings per common share:
Basic (in dollars per share)	$ 1.37	$ 1.28	$ 4.29	$ 4.08
Diluted (in dollars per share)	$ 1.37	$ 1.27	$ 4.27	$ 4.07