EARNINGS PER SHARE - Schedule of Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 24, 2020	Jun. 26, 2019	Jun. 24, 2020	Jun. 26, 2019
Numerator:
Net income (loss)	$ (18,031)	$ 11,171	$ (19,110)	$ 14,778
Less: net income (loss) attributable to non-controlling interests	(1,820)	2,141	(1,939)	3,202
NET INCOME (LOSS) ATTRIBUTABLE TO SHAKE SHACK INC.	$ (16,211)	$ 9,030	$ (17,171)	$ 11,576
Denominator:
Weighted-average shares of Class A common stock outstanding—basic (in shares)	37,309	30,122	35,876	29,842
Effect of dilutive securities:
Weighted-average shares of Class A common stock outstanding—diluted (in shares)	37,309	31,015	35,876	30,703
Earnings per share of Class A common stock—basic (in dollars per share)	$ (0.43)	$ 0.30	$ (0.48)	$ 0.39
Earnings per share of Class A common stock—diluted (in dollars per share)	$ (0.43)	$ 0.29	$ (0.48)	$ 0.38
Performance stock units
Effect of dilutive securities:
Stock options (in shares)	0	68	0	72
Restricted stock units
Effect of dilutive securities:
Stock options (in shares)	0	50	0	36
Stock options
Effect of dilutive securities:
Stock options (in shares)	0	775	0	753