Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 28, 2017	Mar. 29, 2016
Amounts used for basic and diluted per share calculations
Net income attributable to Panera Bread Company	$ 42,494	$ 35,088
Weighted average number of shares outstanding - basic (in shares)	22,488	24,105
Effect of dilutive stock-based employee compensation awards (in shares)	136	109
Weighted average number of shares outstanding - diluted (in shares)	22,624	24,214
Earnings per common share:
Basic (in dollars per share)	$ 1.89	$ 1.46
Diluted (in dollars per share)	$ 1.88	$ 1.45