Shake Shack (SHAK) 10-K 25 Feb 19 2018 Q4 Annual report Financial data

Document and Entity Information

Document and Entity Information Document - USD ($)	12 Months Ended
	Dec. 26, 2018	Feb. 13, 2019	Jun. 27, 2018
Document Information [Line Items]
Document type	10-K
Amendment flag	false
Document period end date	Dec. 26, 2018
Document fiscal year focus	2,018
Document fiscal period focus	Q4
Entity registrant name	Shake Shack Inc.
Entity central index key	1,620,533
Current fiscal year end date	--12-26
Entity filer category	Large Accelerated Filer
Entity current reporting status	Yes
Entity Public Float			$ 1,746,799,325
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Shell Company	false
Entity Emerging Growth Company	false
Entity Small Business	false
Class A Common Stock
Document Information [Line Items]
Entity common stock, shares outstanding (in shares)		29,537,426
Class B Common Stock
Document Information [Line Items]
Entity common stock, shares outstanding (in shares)		7,547,347

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 26, 2018	Dec. 27, 2017
Current assets:
Cash and cash equivalents	$ 24,750	$ 21,507
Marketable securities	62,113	63,036
Accounts receivable	10,523	5,641
Inventories	1,749	1,258
Prepaid expenses and other current assets	1,984	1,757
Total current assets	101,119	93,199
Property and equipment, net	261,854	187,095
Deferred income taxes, net	242,533	185,914
Other assets	5,026	4,398
TOTAL ASSETS	610,532	470,606
Current liabilities:
Accounts payable	12,467	8,210
Accrued expenses	22,799	11,649
Accrued wages and related liabilities	10,652	6,228
Other current liabilities	14,030	7,937
Total current liabilities	59,948	34,024
Deemed landlord financing	20,846	14,518
Deferred rent	47,864	36,596
Liabilities under tax receivable agreement, net of current portion	197,921	158,436
Other long-term liabilities	10,498	2,553
Total liabilities	337,077	246,127
Commitments and contingencies
Stockholders' equity:
Preferred stock, no par value—10,000,000 shares authorized; none issued and outstanding as of December 26, 2018 and December 27, 2017, respectively.	0	0
Additional paid-in capital	195,633	153,105
Retained earnings	30,404	16,399
Accumulated other comprehensive loss	0	(49)
Total stockholders' equity attributable to Shake Shack Inc. / members' equity	226,075	169,492
Non-controlling interests	47,380	54,987
Total equity	273,455	224,479
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	610,532	470,606
Class A common stock, $0.001 par value—200,000,000 shares authorized; 29,520,833 and 26,527,477 shares issued and outstanding as of December 26, 2018 and December 27, 2017, respectively.
Stockholders' equity:
Common stock	30	27
Class B common stock, $0.001 par value—35,000,000 shares authorized; 7,557,347 and 10,250,007 shares issued and outstanding as of December 26, 2018 and December 27, 2017, respectively.
Stockholders' equity:
Common stock	$ 8	$ 10

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 26, 2018	Dec. 27, 2017
Preferred stock, par value (in dollars per share)	$ 0	$ 0
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Class A Common Stock
Common stock par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	200,000,000	200,000,000
Common stock, shares, issued (in shares)	29,520,833	26,527,477
Common stock, shares, outstanding (in shares)	29,520,833	26,527,477
Class B Common Stock
Common stock par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	35,000,000	35,000,000
Common stock, shares, issued (in shares)	7,557,347	10,250,007
Common stock, shares, outstanding (in shares)	7,557,347	10,250,007

CONSOLIDATED STATEMENTS OF INCO

CONSOLIDATED STATEMENTS OF INCOME (LOSS) - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 26, 2018	Dec. 27, 2017	Dec. 28, 2016
TOTAL REVENUE	$ 459,310	$ 358,810	$ 268,475
Shack-level operating expenses:
Food and paper costs	126,096	98,337	73,752
Labor and related expenses	122,094	91,740	65,540
Other operating expenses	51,783	35,805	24,946
Occupancy and related expenses	32,710	28,197	21,820
General and administrative expenses	52,720	39,003	30,556
Depreciation expense	29,000	21,704	14,502
Pre-opening costs	12,279	9,603	9,520
Loss on disposal of property and equipment	917	608	34
TOTAL EXPENSES	427,599	324,997	240,670
OPERATING INCOME	31,711	33,813	27,805
Other income, net	1,514	128,123	1,065
Interest expense	(2,415)	(1,643)	(374)
INCOME BEFORE INCOME TAXES	30,810	160,293	28,496
Income tax expense	8,862	151,409	6,350
NET INCOME	21,948	8,884	22,146
Less: net income attributable to non-controlling interests	6,769	9,204	9,700
Net income (loss) attributable to Shake Shack Inc.	$ 15,179	$ (320)	$ 12,446
Earnings (loss) per share of Class A common stock
Basic (in dollars per share)	$ 0.54	$ (0.01)	$ 0.54
Diluted (in dollars per share)	$ 0.52	$ (0.01)	$ 0.53
Weighted-average shares of Class A common stock outstanding
Basic (shares)	28,299	25,876	22,956
Diluted (shares)	29,179	25,876	23,449
Shack sales
TOTAL REVENUE	$ 445,589	$ 346,388	$ 259,350
Licensing revenue
TOTAL REVENUE	$ 13,721	$ 12,422	$ 9,125

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands		12 Months Ended
		Dec. 26, 2018	Dec. 27, 2017	Dec. 28, 2016
Statement of Comprehensive Income [Abstract]
Net income		$ 21,948	$ 8,884	$ 22,146
Available-for-sale securities:
Change in net unrealized holding (losses)	[1]	(3)	(94)	(35)
Less: reclassification adjustments for net realized losses included in net income	[1]	16	47	19
Net change	[1]	13	(47)	(16)
OTHER COMPREHENSIVE LOSS, NET OF TAX		13	(47)	(16)
COMPREHENSIVE INCOME		21,961	8,837	22,130
Less: comprehensive income attributable to non-controlling interests		6,772	9,191	9,694
COMPREHENSIVE INCOME ATTRIBUTABLE TO SHAKE SHACK INC.		$ 15,189	$ (354)	$ 12,436
[1]	Net of tax benefit of $0 for fiscal years ended December 26, 2018, December 27, 2017 and December 28, 2016.

CONSOLIDATED STATEMENTS OF CO_2

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (Parenthetical) - USD ($)	12 Months Ended
	Dec. 26, 2018	Dec. 27, 2017	Dec. 28, 2016
Statement of Comprehensive Income [Abstract]
Comprehensive income net of tax benefit	$ 0	$ 0	$ 0

CONSOLIDATED STATEMENTS OF STOC

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' AND MEMBERS' EQUITY - USD ($) $ in Thousands	Total	Class A Common Stock	Class B Common Stock	Common stockClass A Common Stock	Common stockClass B Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Non- Controlling Interest	Secondary Offering and Redemption of Units	Secondary Offering and Redemption of UnitsCommon stockClass A Common Stock	Secondary Offering and Redemption of UnitsCommon stockClass B Common Stock	Secondary Offering and Redemption of UnitsAdditional Paid-In Capital	Secondary Offering and Redemption of UnitsNon- Controlling Interest
Beginning balance at Dec. 30, 2015	$ 157,019			$ 20	$ 16	$ 96,311	$ 4,273	$ (5)	$ 56,404
Beginning balance (in shares) at Dec. 30, 2015				19,789,259	16,460,741
Other comprehensive loss:
Net unrealized losses related to available-for-sale securities	(16)							(10)	(6)
Equity-based compensation	5,493					5,493
Establishment of liabilities under tax receivable agreement and related changes to deferred tax assets associated with increases in tax basis	15,833					15,833
Redemptions (in shares)											(5,207,149)	(5,207,149)
Redemptions										$ 0	$ 5	$ (5)	$ 16,986	$ (16,986)
Net income	22,146						12,446		9,700
Stock option exercises (in shares)				154,976
Stock option exercises	3,197			$ 0		795			2,402
Income tax effect of stock compensation plans	33					30			3
Distributions paid and payable to non-controlling interest holders	(2,352)								(2,352)
Ending balance at Dec. 28, 2016	201,353			$ 25	$ 11	135,448	16,719	(15)	49,165
Ending balance (in shares) at Dec. 28, 2016				25,151,384	11,253,592
Other comprehensive loss:
Net unrealized losses related to available-for-sale securities	(47)							(34)	(13)
Equity-based compensation	5,732					5,732
Establishment of liabilities under tax receivable agreement and related changes to deferred tax assets associated with increases in tax basis	3,059					3,059
Redemptions (in shares)				(1,003,585)							(1,003,585)	(1,003,585)
Redemptions									(4,415)	0	$ 1	$ (1)	4,415
Net income	8,884						(320)		9,204
Stock option exercises (in shares)				372,508
Stock option exercises	7,270			$ 1		4,451			2,818
Distributions paid and payable to non-controlling interest holders	(1,772)								(1,772)
Ending balance at Dec. 27, 2017	224,479			$ 27	$ 10	153,105	16,399	(49)	54,987
Ending balance (in shares) at Dec. 27, 2017		26,527,477	10,250,007	26,527,477	10,250,007
Other comprehensive loss:
Net income	4,979
Beginning balance at Dec. 27, 2017	224,479			$ 27	$ 10	153,105	16,399	(49)	54,987
Beginning balance (in shares) at Dec. 27, 2017		26,527,477	10,250,007	26,527,477	10,250,007
Other comprehensive loss:
Net unrealized losses related to available-for-sale securities	13							10	3
Equity-based compensation	6,250					6,250
Establishment of liabilities under tax receivable agreement and related changes to deferred tax assets associated with increases in tax basis	18,567					18,567
Redemptions (in shares)				(2,692,660)							(2,692,660)	(2,692,660)
Redemptions									(15,202)	$ 0	$ 2	$ (2)	$ 15,202
Net income	21,948						15,179		6,769
Stock option exercises (in shares)				300,696
Stock option exercises	4,523			$ 1		2,509			2,013
Distributions paid and payable to non-controlling interest holders	(751)								(751)
Ending balance at Dec. 26, 2018	273,455			$ 30	$ 8	$ 195,633	30,404	0	47,380
Ending balance (in shares) at Dec. 26, 2018		29,520,833	7,557,347	29,520,833	7,557,347
Cumulative Effect of New Accounting Principle in Period of Adoption	$ (1,574)						$ (1,174)	$ 39	$ (439)

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($)	12 Months Ended
	Dec. 26, 2018	Dec. 27, 2017	Dec. 28, 2016
OPERATING ACTIVITIES
Net income (including amounts attributable to non-controlling interests)	$ 21,948,000	$ 8,884,000	$ 22,146,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation expense	29,000,000	21,704,000	14,502,000
Equity-based compensation	6,143,000	5,623,000	5,354,000
Deferred income taxes	788,000	146,334,000	(523,000)
Non-cash interest expense	72,000	317,000	304,000
Excess tax benefits on equity-based compensation	0	0	(33,000)
Loss on sale of marketable securities	16,000	5,000	18,000
Loss on disposal of property and equipment	917,000	608,000	34,000
Other non-cash expense (income)	(78,000)	(127,221,000)	(688,000)
Gain (Loss) on Sublease	672,000	0	0
Changes in operating assets and liabilities:
Accounts receivable	5,530,000	6,421,000	2,974,000
Inventories	(491,000)	(452,000)	(263,000)
Prepaid expenses and other current assets	(270,000)	2,244,000	(756,000)
Other assets	(2,726,000)	(446,000)	(822,000)
Accounts payable	3,156,000	1,235,000	839,000
Accrued expenses	7,979,000	4,388,000	5,560,000
Accrued wages and related liabilities	4,424,000	144,000	280,000
Other current liabilities	860,000	(988,000)	2,130,000
Deferred rent	1,247,000	1,008,000	3,415,000
Other long-term liabilities	6,208,000	1,070,000	(186,000)
NET CASH PROVIDED BY OPERATING ACTIVITIES	85,395,000	70,878,000	54,285,000
INVESTING ACTIVITIES
Purchases of property and equipment	(87,525,000)	(61,533,000)	(54,433,000)
Purchases of marketable securities	(1,223,000)	(7,861,000)	(61,266,000)
Sales of marketable securities	2,144,000	7,451,000	938,000
NET CASH USED IN INVESTING ACTIVITIES	(86,604,000)	(61,943,000)	(114,761,000)
FINANCING ACTIVITIES
Payments on promissory note	0	0	(313,000)
Proceeds from deemed landlord financing	1,382,000	1,183,000	65,000
Payments on deemed landlord financing	(702,000)	(266,000)	0
Distributions paid to non-controlling interest holders	(751,000)	(2,379,000)	(1,745,000)
Payments under tax receivable agreement	0	(4,844,000)	0
Proceeds from stock option exercises	5,472,000	7,585,000	3,194,000
Employee withholding taxes related to net settled equity awards	(949,000)	(314,000)	0
Excess tax benefits from equity-based compensation	0	0	33,000
NET CASH PROVIDED BY FINANCING ACTIVITIES	4,452,000	965,000	1,234,000
INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	3,243,000	9,900,000	(59,242,000)
CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD	21,507,000	11,607,000	70,849,000
CASH AND CASH EQUIVALENTS AT END OF PERIOD	$ 24,750,000	$ 21,507,000	$ 11,607,000

NATURE OF OPERATIONS

NATURE OF OPERATIONS	12 Months Ended
	Dec. 26, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
NATURE OF OPERATIONS	NATURE OF OPERATIONS Sha ke Shack Inc. was formed on September 23, 2014 as a Delaware corporation for the purpose of facilitating an initial public offering and other related tran sactions in order to carry on the business of SSE Holdings, LLC and its subsidiaries. Unless the context otherwise requires, references to "we," "us," "our," "Shake Shack" and the "Company" refer to Shake Shack Inc. and its subsidiaries, including SSE Holdings, LLC, which we refer to as "SSE Holdings." We operate and license Shake Shack restaurants ("Shacks"), which serve hamburgers, hot dogs, chicken, crinkle cut fries, shakes, frozen custard, beer, wine and more. As of December 26, 2018 , there were 208 Shacks in operation, system-wide, of which 124 were domestic company-operated Shacks, 12 were domestic licensed Shacks and 72 were international licensed Shacks.

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	12 Months Ended
	Dec. 26, 2018
Accounting Policies [Abstract]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Basis of Presentation The accompanying consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) and include our accounts and the accounts of our subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation. Certain reclassifications have been made to prior period amounts to conform to the current year presentation. SSE Holdings is considered a variable interest entity. Shake Shack Inc. is the primary beneficiary as we have the majority economic interest in SSE Holdings and, as the sole managing member, have decision making authority that significantly affects the economic performance of the entity, while the limited partners have no substantive kick-out or participating rights. As a result, we will continue to consolidate SSE Holdings. The assets and liabilities of SSE Holdings represent substantially all of our consolidated assets and liabilities with the exception of certain deferred taxes and liabilities under the Tax Receivable Agreement. As of December 26, 2018 and December 27, 2017 , the net assets of SSE Holdings were $232,711 and $197,301 , respectively. The assets of SSE Holdings are subject to certain restrictions in SSE Holdings' revolving credit agreements. See Note 9 for more information. Fiscal Year We operate on a 52/53 week fiscal year ending on the last Wednesday in December. Fiscal year 2018 contained 52 weeks and ended on December 26, 2018 . Fiscal year 2017 contained 52 weeks and ended on December 27, 2017 . Fiscal year 2016 contained 52 weeks and ended on December 28, 2016 . Unless otherwise stated, references to years in this report relate to fiscal years. Use of Estimates The preparation of these consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of sales and expenses during the reporting period. Actual results could differ from those estimates. Segment Reporting We own and operate Shacks in the United States. We also have domestic and international licensed operations. Our chief operating decision maker (the "CODM") is our Chief Executive Officer. As the CODM reviews financial performance and allocates resources at a consolidated level on a recurring basis, we have one operating segment and one reportable segment. Fair Value Measurements We apply fair value accounting for all financial assets and liabilities and non-financial assets and liabilities that are recognized or disclosed at fair value in the financial statements on a recurring basis. Fair value is defined as the price that would be received from selling an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. When determining the fair value measurements for assets and liabilities that are required to be recorded at fair value, we assume the highest and best use of the asset by market participants in which we would transact and the market-based risk measurements or assumptions that market participants would use in pricing the asset or liability, such as inherent risk, transfer restrictions, and credit risk. Assets and liabilities are classified using a fair value hierarchy, which prioritizes the inputs used to measure fair value into three levels, and bases the categorization within the hierarchy upon the lowest level of input that is available and significant to the fair value measurement: ▪ Level 1 - Quoted prices in active markets for identical assets or liabilities ▪ Level 2 - Observable inputs other than quoted prices in active markets for identical assets or liabilities, quoted prices for identical assets or liabilities in inactive markets, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities ▪ Level 3 - Inputs that are both unobservable and significant to the overall fair value measurements reflecting an entity's estimates of assumptions that market participants would use in pricing the asset or liability Cash and Cash Equivalents Cash and cash equivalents consist primarily of cash on hand, deposits with banks, and short-term, highly liquid investments that have original maturities of three months or less. Cash equivalents are stated at cost, which approximates fair value. Cash equivalents consist primarily of money market funds. Accounts Receivable Accounts receivable consist primarily of receivables from landlords for tenant improvement allowances, receivables from our licensees for licensing revenue and related reimbursements, credit card receivables and vendor rebates. We evaluate the collectibility of our accounts receivable based on a variety of factors, including historical experience, current economic conditions and other factors. Inventories Inventories, which consist of food, beer, wine, other beverages and retail merchandise, are stated at the lower of cost or net realizable value with cost determined on a first-in, first-out basis. No adjustment is deemed necessary to reduce inventory to net realizable value due to the rapid turnover and high utilization of inventory. Property and Equipment Property and equipment is stated at historical cost less accumulated depreciation. Property and equipment is depreciated based on the straight-line method over the estimated useful lives of the assets, generally ranging from three to seven years for equipment, furniture and fixtures, and computer equipment and software. Leasehold improvements are depreciated over the shorter of their estimated useful life or the related lease life, generally ranging from 10 to 15 years. Landlord funded assets are depreciated over the shorter of their estimated useful life or the related lease life, generally ranging from 10 to 15 years. For leases with renewal periods at our option, we use the original lease term, excluding renewal option periods, to determine estimated useful lives. Costs incurred when constructing Shacks are capitalized. The cost of repairs and maintenance are expensed when incurred. Costs for refurbishments and improvements that significantly increase the productive capacity or extend the useful life of the asset are capitalized. When assets are disposed of, the resulting gain or loss is recognized on the Consolidated Statements of Income (Loss). We assess potential impairments to our long-lived assets, which includes property and equipment, whenever events or circumstances indicate that the carrying amount of an asset may not be recoverable. Recoverability of an asset is measured by a comparison of the carrying amount of an asset group to its estimated undiscounted future cash flows expected to be generated by the asset. If the carrying amount of the asset group exceeds its estimated undiscounted future cash flows, an impairment charge is recognized as the amount by which the carrying amount of the asset exceeds the fair value of the asset. There were no impairment charges recorded in fiscal 2018 , 2017 and 2016 . Deferred Financing Costs Deferred financing costs incurred in connection with the issuance of long-term debt and establishing credit facilities are capitalized and amortized to interest expense based on the related debt agreements. Deferred financing costs are included in other assets on the Consolidated Balance Sheets. Other Assets Other assets consist primarily of capitalized implementation costs from cloud computing arrangements, long-term marketable securities, security deposits, transferable liquor licenses and certain custom furniture pre-ordered for future Shacks and yet to be placed in service. The costs of obtaining non-transferable liquor licenses that are directly issued by local government agencies for nominal fees are expensed as incurred. The costs of purchasing transferable liquor licenses through open markets in jurisdictions with a limited number of authorized liquor licenses are capitalized as indefinite-lived intangible assets. Annual liquor license renewal fees are expensed over the renewal term. As of December 26, 2018 and December 27, 2017 , indefinite-lived intangible assets relating to transferable liquor licenses totaled $1,159 and $894 , respectively. We evaluate our indefinite-lived intangible assets for impairment annually during our fiscal fourth quarter, and whenever events or changes in circumstances indicate that an impairment may exist. When evaluating other intangible assets for impairment, we may first perform a qualitative assessment to determine whether it is more likely than not that an intangible asset group is impaired. If we do not perform the qualitative assessment, or if we determine that it is not more likely than not that the fair value of the intangible asset group exceeds its carrying amount, we calculate the estimated fair value of the intangible asset group. If the carrying amount of the intangible asset group exceeds the estimated fair value, an impairment charge is recorded to reduce the carrying value to the estimated fair value. In addition, we continuously monitor and may revise our intangible asset useful lives if and when facts and circumstances change. Equity-based Compensation Equity-based compensation expense is measured based on fair value. For awards with graded-vesting features and service conditions only, compensation expense is recognized on a straight-line basis over the total requisite service period for the entire award. For awards with graded-vesting features and a combination of service and performance conditions, compensation expense is recognized using a graded-vesting attribution method over the vesting period based on the most probable outcome of the performance conditions. Forfeitures are recognized as they occur for all equity awards. Equity-based compensation expense is included within general and administrative expenses and labor and related expenses on the Consolidated Statements of Income (Loss) . Leases We lease all of our domestic company-operated Shacks, our Home Office and certain equipment under various non-cancelable lease agreements that expire on various dates through 2035. Generally, our real estate leases have initial terms ranging from 10 to 15 years and typically include two five -year renewal options. At the inception of each lease, we determine its classification as an operating or capital lease. Most of our leases are classified as operating leases and typically provide for fixed minimum rent payments and/or contingent rent payments based upon sales in excess of specified thresholds. When the achievement of such sales thresholds are deemed to be probable, contingent rent is accrued in proportion to the sales recognized during the period. For operating leases that include rent holidays and rent escalation clauses, we recognize rent expense on a straight-line basis over the lease term from the date we take possession of the leased property. The difference between the straight-line rent amounts and amounts payable under the lease agreements is recorded as deferred rent and is included as rent expense in occupancy and related expenses on the Consolidated Statements of Income (Loss) . Rent expense incurred before a Shack opens is recorded in pre-opening costs. Once a domestic company-operated Shack opens, we record the straight-line rent expense and any contingent rent, if applicable, in occupancy and related expenses on the Consolidated Statements of Income (Loss) . Many of our leases also require us to pay real estate taxes, common area maintenance costs and other occupancy costs which are included in occupancy and related expenses on the Consolidated Statements of Income (Loss) . We expend cash for leasehold improvements to build out and equip our leased premises. Generally, a portion of the leasehold improvements and building costs are reimbursed by our landlords as landlord incentives pursuant to agreed-upon terms in our lease agreements. If obtained, landlord incentives usually take the form of up-front cash, full or partial credits against our future minimum or contingent rents otherwise payable by us, or a combination thereof. When contractually due, we classify landlord incentives as deferred rent on the Consolidated Balance Sheets and amortize the landlord incentives on a straight-line basis over the lease term as a reduction of occupancy costs and related expenses or pre-opening costs on the Consolidated Statements of Income (Loss) . Lease Financing Arrangements In certain leasing arrangements, due to our involvement in the construction of the leased assets, we are considered the owner of the leased assets for accounting purposes. In such cases, in addition to capitalizing our own construction costs, we capitalize the construction costs funded by the landlord related to our leased premises, and also recognize a corresponding liability for those costs as deemed landlord financing. If, upon completion of construction, the arrangement does not meet the sales recognition criteria under the sale-leaseback accounting guidance, we are precluded from de-recognizing the landlord-funded asset and related financing obligation and continue to account for the landlord-funded asset as if we were the legal owner. If de-recognition is permitted we are required to account for the lease as either an operating or capital lease. As of December 26, 2018 , we were deemed to be the accounting owner of 24 leased Shacks, one of which was under construction as of the end of the period. As of December 27, 2017 , we were deemed to be the accounting owner of 23 leased Shacks, 11 of which were under construction as of the end of the period. Revenue Recognition Revenue consists of Shack sales and licensing revenue. Generally, revenue is recognized as promised goods or services transfer to the guest or customer in an amount that reflects the consideration we expect to be entitled in exchange for those goods or services. Revenue from Shack sales is presented net of discounts and recognized when food, beverage and retail products are sold. Sales tax collected from customers is excluded from Shack sales and the obligation is included in sales tax payable until the taxes are remitted to the appropriate taxing authorities. Revenue from our gift cards is deferred and recognized upon redemption. Licensing revenues include initial territory fees, Shack opening fees, and ongoing sales-based royalty fees from licensed Shacks. Income Taxes We account for income taxes pursuant to the asset and liability method which requires the recognition of deferred income tax assets and liabilities related to the expected future tax consequences arising from temporary differences between the carrying amounts and tax bases of assets and liabilities based on enacted statutory tax rates applicable to the periods in which the temporary differences are expected to reverse. Any effects of changes in income tax rates or laws are included in income tax expense in the period of enactment. A valuation allowance is recognized if we determine it is more likely than not that all or a portion of a deferred tax asset will not be recognized. Pre-Opening Costs Pre-opening costs are expensed as incurred and consist primarily of legal fees, marketing expenses, occupancy, manager and employee wages, travel and related training costs incurred prior to the opening of a Shack. Advertising The cost of advertising is expensed as incurred. Advertising costs amounted to $399 , $357 and $147 in fiscal 2018 , 2017 and 2016 , respectively, and are included in general and administrative expense and other operating expenses on the Consolidated Statements of Income (Loss) . Recently Adopted Accounting Pronouncements We adopted the Accounting Standards Updates (“ASUs”) summarized below in fiscal 2018. Accounting Standards Update (“ASU”) Description Date Adopted Revenue from Contracts with Customers and related standards (ASU’s 2014-09, 2015-14, 2016-08, 2016-10, 2016-12, 2016-20) This standard supersedes the existing revenue recognition guidance and provides a new framework for recognizing revenue. The core principle of the standard is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods and services. The new standard also requires significantly more comprehensive disclosures than the existing standard. Guidance subsequent to ASU 2014-09 has been issued to clarify various provisions in the standard, including principal versus agent considerations, identifying performance obligations, licensing transactions, as well as various technical corrections and improvements. See Note 3 for more information. December 28, 2017 Recognition and Measurement of Financial Assets and Financial Liabilities (ASU 2016-01) For public business entities, this standard requires: (i) certain equity investments to be measured at fair value with changes in fair value recognized in net income; (ii) a qualitative assessment to identify impairment of equity investments without readily determinable fair values; (iii) elimination of the requirement to disclose the method(s) and significant assumptions used to estimate the fair value for financial instruments measured at amortized cost on the balance sheet; (iv) use of the exit price notion when measuring the fair value of financial instruments for disclosure purposes; (v) separate presentation in other comprehensive income of the portion of the total change in the fair value of a liability resulting from a change in the instrument-specific credit risk when the entity has elected to measure the liability at fair value in accordance with the fair value option for financial instruments; (vi) separate presentation of financial assets and liabilities by measurement category and form of financial asset in the financial statements; and (vii) an entity to evaluate the need for a valuation allowance on a deferred tax asset related to available-for-sale securities in combination with the entity’s other deferred tax assets. The adoption of this standard did not have a material impact to our consolidated financial statements. December 28, 2017 Statement of Cash Flows: Classification of Certain Cash Receipts and Payments (ASU 2016-15) This standard provides guidance on eight specific cash flow issues with the objective of reducing diversity in practice. The adoption of this standard did not have a material impact to our consolidated financial statements. December 28, 2017 Customer's Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract (ASU 2018-15) This standard provides additional guidance on accounting for costs of implementation activities performed in a cloud computing arrangement that is a service contract. The standard aligns the requirements for capitalizing implementation costs of such arrangements with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software. The standard also clarifies the presentation and classification of the capitalized costs, amortization expense, and the associated treatment in the statement of cash flows by aligning these items with the same treatment for costs of the hosting service itself. We adopted this standard on a prospective basis on September 27, 2018, and began capitalizing certain costs related to the implementation of an enterprise-wide system initiative that previously would have been expensed. As of December 26, 2018, we have capitalized certain implementation costs within other assets. We will begin amortizing the implementation costs once the system is ready for its intended use, on a straight-line basis, over the term of the related service agreements. The amortization expense related to cloud computing arrangements that are service contracts will be recorded within general and administrative expenses. September 27, 2018 Recently Issued Accounting Pronouncements Accounting Standards Update (“ASU”) Description Expected Impact Effective Date Leases (ASU's 2016-02, 2018-01, 2018-10, 2018-11) This standard establishes a new lease accounting model, which introduces the recognition of lease assets and liabilities for those leases classified as operating leases under previous GAAP. It should be applied using a modified retrospective approach applied either at the beginning of the earliest period presented, or at the adoption date, with the option to elect various practical expedients. Early adoption is permitted. We will adopt the standard on December 27, 2018, electing the optional transition method to apply the standard as of the transition date. As a result, we will not apply the standard to the comparative periods presented. We have elected the transition package of three practical expedients permitted under the new standard, which among other things, allows us to carryforward our historical lease classifications. We also made certain accounting policy elections for new leases post-transition, including the election to combine components. The adoption will have a significant impact to our consolidated balance sheet given the extent of our real estate lease portfolio. We will derecognize all landlord funded assets, deemed financing liabilities and deferred rent liabilities upon transition. We will record a right-of-use asset and lease liability for those leases as well as all other existing leases, the majority of which are real estate operating leases. We expect the adoption to result in a net increase of between $207,000 to $217,000 in lease assets and $202,000 to $212,000 in lease liabilities. The difference between the additional lease assets and lease liabilities, net of tax, will be recorded as an adjustment through equity. Our existing operating leases will not have a material impact on our statement of income post-transition. For those leases where we are involved in construction and deemed to be the accounting owner, they will be accounted for as operating leases post-transition, resulting in an increase to occupancy and related expenses, and a decrease to interest and depreciation expense. We are substantially complete with our implementation efforts. December 27, 2018

REVENUE (Notes)

REVENUE (Notes)	12 Months Ended
	Dec. 26, 2018
Revenue from Contract with Customer [Abstract]
Revenue from Contract with Customer [Text Block]	REVENUE On December 28, 2017 we adopted ASU 2014-09, Revenue from Contracts with Customers (Topic 606) , using the modified retrospective method applied to those contracts which were not completed as of December 28, 2017. We elected a practical expedient to aggregate the effect of all contract modifications that occurred before the adoption date, which did not have a material impact to our consolidated financial statements. Results for reporting periods beginning on or after December 28, 2017 are presented under Accounting Standards Codification Topic 606 ("ASC 606"). Prior period amounts were not revised and continue to be reported in accordance with ASC Topic 605 ("ASC 605"), the accounting standard then in effect. Upon transition, on December 28, 2017, we recorded a decrease to opening equity of $1,574 , net of tax, of which $1,135 was recognized in retained earnings and accumulated other comprehensive income (loss) and $439 in non-controlling interest, with a corresponding increase of $1,769 in other long-term liabilities, a decrease of $68 in other current liabilities and an increase of $100 to accounts receivable. Revenue Recognition Revenue consists of Shack sales and licensing revenue. Generally, revenue is recognized as promised goods or services transfer to the guest or customer in an amount that reflects the consideration we expect to be entitled in exchange for those goods or services. Revenue from Shack sales is presented net of discounts and recognized when food, beverage and retail products are sold. Sales tax collected from customers is excluded from Shack sales and the obligation is included in sales tax payable until the taxes are remitted to the appropriate taxing authorities. Revenue from our gift cards is deferred and recognized upon redemption. Licensing revenues include initial territory fees, Shack opening fees and ongoing sales-based royalty fees from licensed Shacks. Generally, the licenses granted to develop, open and operate each Shack in a specified territory are the predominant goods or services transferred to the licensee in our contracts, and represent distinct performance obligations. Ancillary promised services, such as training and assistance during the initial opening of a Shack, are typically combined with the licenses and considered as one performance obligation per Shack. We determine the transaction price for each contract, which is comprised of the initial territory fee and an estimate of the total Shack opening fees we expect to be entitled to. The calculation of total Shack opening fees included in the transaction price requires judgment, as it is based on an estimate of the number of Shacks we expect the licensee to open. The transaction price is then allocated equally to each Shack expected to open. The performance obligations are satisfied over time, starting when a Shack opens, through the end of the term of the license granted to the Shack. Because we are transferring licenses to access our intellectual property during a contractual term, revenue is recognized on a straight-line basis over the license term. Generally, payment for the initial territory fee is received upon execution of the licensing agreement and payment for the restaurant opening fees are received either in advance of or upon opening the related restaurant. These payments are initially deferred and recognized as revenue as the performance obligations are satisfied, which occurs over a long-term period. Revenue from sales-based royalties is recognized as the related sales occur. Prior to the adoption of ASC 606, Shack opening fees were recorded as deferred revenue when received and proportionate amounts were recognized as revenue when a licensed Shack opened and all material services and conditions related to the fee were substantially performed. Territory fees were recorded as deferred revenue when received and recognized as revenue on a straight-line basis over the term of the license agreement, which generally began upon execution of the contract. Revenue recognized during fiscal 2018 under ASC 606 and revenue that would have been recognized during fiscal 2018 had ASC 605 been applied is as follows: As reported under ASC 606 If reported under ASC 605 Increase (decrease) Shack sales $ 445,589 $ 445,589 $ — Licensing revenue 13,721 14,389 (668 ) Total revenue $ 459,310 $ 459,978 $ (668 ) Revenue recognized during fiscal 2018 (under ASC 606) and fiscal 2017 and 2016 (under ASC 605) disaggregated by type is as follows: December 26 December 27 December 28 Shack sales $ 445,589 $ 346,388 $ 259,350 Licensing revenue: Sales-based royalties 13,422 11,633 8,765 Initial territory and opening fees 299 789 360 Total revenue $ 459,310 $ 358,810 $ 268,475 The aggregate amount of the transaction price allocated to performance obligations that are unsatisfied (or partially unsatisfied) as of December 26, 2018 is $15,333 . We expect to recognize this amount as revenue over a long-term period, as the license term for each Shack ranges from 5 to 20 years. This amount excludes any variable consideration related to sales-based royalties. Contract Balances Opening and closing balances of contract liabilities and receivables from contracts with customers for fiscal 2018 is as follows: December 26 December 28 Shack sales receivables $ 2,550 $ 2,184 Licensing receivables 2,616 1,522 Gift card liability 1,796 1,472 Deferred revenue, current 307 265 Deferred revenue, long-term 10,026 3,742 Revenue recognized during fiscal 2018 that was included in the balances of gift card liability and deferred revenue, current, at the beginning of the period is $506 and $253 , respectively.

FAIR VALUE MEASUREMENTS

FAIR VALUE MEASUREMENTS	12 Months Ended
	Dec. 26, 2018
Fair Value Disclosures [Abstract]
FAIR VALUE MEASUREMENTS	FAIR VALUE MEASUREMENTS Assets and Liabilities Measured at Fair Value on a Recurring Basis The following tables present information about our financial assets and liabilities measured at fair value on a recurring basis as of December 26, 2018 and December 27, 2017 , and indicate the classification within the fair value hierarchy. Refer to Note 2 for further information. Cash, Cash Equivalents and Marketable Securities The following tables summarize our cash, cash equivalents and marketable securities by significant investment categories as of December 26, 2018 and December 27, 2017 : December 26, 2018 Cost Basis Gross Unrealized Gains Gross Unrealized Losses Fair Value Cash and Cash Equivalents Marketable Securities Cash $ 19,746 $ — $ — $ 19,746 $ 19,746 $ — Level 1: Money market funds 5,004 — — 5,004 5,004 — Mutual funds 62,235 — (122 ) 62,113 — 62,113 Level 2: Corporate debt securities (1) — — — — — — Total $ 86,985 $ — $ (122 ) $ 86,863 $ 24,750 $ 62,113 December 27, 2017 Cost Basis Gross Unrealized Gains Gross Unrealized Losses Fair Value Cash and Cash Equivalents Marketable Securities Cash $ 16,138 $ — $ — $ 16,138 $ 16,138 $ — Level 1: Money market funds 5,369 — — 5,369 5,369 — Mutual funds 60,985 — (61 ) 60,924 — 60,924 Level 2: Corporate debt securities (1) 2,125 2 (15 ) 2,112 — 2,112 Total $ 84,617 $ 2 $ (76 ) $ 84,543 $ 21,507 $ 63,036 (1) Corporate debt securities were measured at fair value using a market approach utilizing observable prices for identical securities or securities with similar characteristics and inputs that are observable or can be corroborated by observable market data. On December 28, 2017, we adopted ASU 2016-01, which requires certain equity investments to be measured at fair value with changes in fair value recognized in net income. Net un realized losses on available-for-sale equity securities totaling $61 were included on the Condensed Consolidated Statements of Income during fiscal 2018 . Net unrealized losses on available-for-sale securities totaling $74 were included in accumulated other comprehensive loss on the Condensed Consolidated Balance Sheet as of December 27, 2017 . The following tables summarize the gross unrealized losses and fair values for investments in debt securities that were in an unrealized loss position as of December 26, 2018 and December 27, 2017 , aggregated by length of time that individual securities have been in a continuous loss position: Less than 12 Months 12 Months or Greater Total Fair Value Unrealized Loss Fair Value Unrealized Loss Fair Value Unrealized Loss As of December 26, 2018 — — — — — — As of December 27, 2017 1,675 (12 ) 162 (3 ) 1,837 (15 ) A summary of other income from available-for-sale securities recognized during fiscal 2018 , 2017 and 2016 is as follows: 2018 2017 2016 Available-for-sale securities: Dividend income $ 1,392 $ 830 $ 296 Interest income 9 77 88 Loss on investments (3 ) (5 ) (7 ) Unrealized loss on available-for-sale equity securities (61 ) — — Total other income, net $ 1,337 $ 902 $ 377 A summary of available-for-sale securities sold and gross realized gains and losses recognized during fiscal 2018 , 2017 and 2016 is as follows: 2018 2017 2016 Available-for-sale securities: Gross proceeds from sales and redemptions $ 2,144 $ 2,223 $ 938 Cost basis of sales and redemptions 2,160 2,271 956 Gross realized gains included in net income 2 1 2 Gross realized losses included in net income (18 ) (49 ) (20 ) Amounts reclassified out of accumulated other comprehensive loss 16 47 19 Realized gains and losses are determined on a specific identification method and are included in other income, net on the Consolidated Statements of Income (Loss) . We periodically review our marketable securities for other-than-temporary impairment. We consider factors such as the duration, severity and the reason for the decline in value, the potential recovery period and our intent to sell. For our debt securities, we also considered whether (i) it is more likely than not that we will be required to sell the debt securities before recovery of their amortized cost basis, and (ii) the amortized cost basis cannot be recovered as a result of credit losses. As of December 26, 2018 and December 27, 2017 , the declines in the market value of our marketable securities investment portfolio are considered to be temporary in nature. Other Financial Instruments The carrying value of our financial instruments, including accounts receivable, accounts payable, and accrued expenses as of December 26, 2018 and December 27, 2017 approximated their fair value due to the short-term nature of these financial instruments. Assets and Liabilities Measured at Fair Value on a Non-Recurring Basis Assets and liabilities that are measured at fair value on a non-recurring basis include our long-lived assets and indefinite-lived intangible assets. There were no impairments recognized during fiscal 2018 , 2017 and 2016 .

ACCOUNTS RECEIVABLE

ACCOUNTS RECEIVABLE	12 Months Ended
	Dec. 26, 2018
Receivables [Abstract]
ACCOUNTS RECEIVABLE	ACCOUNTS RECEIVABLE The components of accounts receivable as of December 26, 2018 and December 27, 2017 are as follows: December 26 December 27 Landlord receivables $ 4,494 $ 1,660 Licensing receivables 2,579 1,422 Credit card receivables 2,446 2,018 Other receivables 1,004 541 Accounts receivable $ 10,523 $ 5,641 As of December 26, 2018 and December 27, 2017 , no allowance for doubtful accounts was recorded based on our evaluation of collectibility.

INVENTORIES

INVENTORIES	12 Months Ended
	Dec. 26, 2018
Inventory Disclosure [Abstract]
INVENTORIES	INVENTORIES Inventories consisted of the following: December 26 December 27 Food $ 1,291 $ 874 Wine 83 69 Beer 95 85 Beverages 203 111 Retail merchandise 77 119 Inventories $ 1,749 $ 1,258

PROPERTY AND EQUIPMENT

PROPERTY AND EQUIPMENT	12 Months Ended
	Dec. 26, 2018
Property, Plant and Equipment [Abstract]
PROPERTY AND EQUIPMENT	PROPERTY AND EQUIPMENT Property and equipment consisted of the following: December 26 December 27 Leasehold improvements $ 228,453 $ 166,963 Landlord funded assets 15,595 7,472 Equipment 40,716 31,608 Furniture and fixtures 14,055 10,128 Computer equipment and software 19,008 12,721 Construction in progress (includes assets under construction from deemed landlord financing) 29,474 16,458 Property and equipment, gross 347,301 245,350 Less: accumulated depreciation (85,447 ) (58,255 ) Property and equipment, net $ 261,854 $ 187,095 Depreciation expense was $29,000 , $21,704 and $14,502 for fiscal 2018 , 2017 and 2016 , respectively.

SUPPLEMENTAL BALANCE SHEET INFO

SUPPLEMENTAL BALANCE SHEET INFORMATION	12 Months Ended
	Dec. 26, 2018
Supplemental Balance Sheet Disclosures [Abstract]
SUPPLEMENTAL BALANCE SHEET INFORMATION	SUPPLEMENTAL BALANCE SHEET INFORMATION The components of other current liabilities as of December 26, 2018 and December 27, 2017 are as follows: December 26 December 27 Sales tax payable $ 3,143 $ 1,813 Current portion of liabilities under tax receivable agreement 5,804 937 Gift card liability 1,796 1,472 Other 3,287 3,715 Other current liabilities $ 14,030 $ 7,937

DEBT

DEBT	12 Months Ended
	Dec. 26, 2018
Debt Disclosure [Abstract]
DEBT	DEBT In January 2015, we executed a Third Amended and Restated Credit Agreement, which became effective on February 4, 2015 (together with the prior agreements and amendments, and as further amended, the "Revolving Credit Facility"), which provides for a total revolving commitment amount of $50,000 , of which $20,000 is available immediately. The Revolving Credit Facility will mature and all amounts outstanding will be due and payable five years from the effective date. The Revolving Credit Facility permits the issuance of letters of credit upon our request of up to $10,000 . In May 2016, the Revolving Credit Facility was amended to, among other things, lower the borrowing rates. Borrowings under the Revolving Credit Facility bear interest at either: (i) LIBOR plus a percentage ranging from 2.3% to 3.3% or (ii) the prime rate plus a percentage ranging from 0.0% to 0.8% , depending on the type of borrowing made under the Revolving Credit Facility. As of December 26, 2018 and December 27, 2017 , there were no amounts outstanding under the Revolving Credit Facility. As of December 26, 2018 , we had $19,317 of availability under the Revolving Credit Facility, after giving effect to $683 in outstanding letters of credit. The Revolving Credit Facility is secured by a first-priority security interest in substantially all of the assets of SSE Holdings and the guarantors. The obligations under the Revolving Credit Facility are guaranteed by each of SSE Holdings' wholly-owned domestic subsidiaries (with certain exceptions). The Revolving Credit Facility contains a number of covenants that, among other things, limit our ability to, subject to specified exceptions, incur additional debt; incur additional liens and contingent liabilities; sell or dispose of assets; merge with or acquire other companies; liquidate or dissolve ourselves; pay dividends or make distributions; engage in businesses that are not in a related line of business; make loans, advances or guarantees; engage in transactions with affiliates; and make investments. In addition, the Revolving Credit Facility contains certain cross-default provisions. We are required to maintain a specified consolidated fixed-charge coverage ratio and a specified funded net debt to adjusted EBITDA ratio, both as defined under the Revolving Credit Facility. As of December 26, 2018 , we were in compliance with all covenants. In March 2013, we entered into a promissory note in the amount of $313 in connection with the purchase of a liquor license, and we repaid the entire outstanding balance of the promissory note during the fiscal year ended December 28, 2016 . As of December 26, 2018 and December 27, 2017 we had deemed landlord financing liabilities of $20,846 and $14,518 , respectively, for certain leases where we are involved in the construction of leased assets and are considered the accounting owner of the construction project. Refer to Note 10 for further details regarding these leases. Total interest costs incurred were $2,572 , $1,806 and $374 in fiscal 2018 , 2017 and 2016 , respectively. Amounts capitalized into property and equipment were $157 and $164 during fiscal 2018 and 2017 , respectively. No amounts were capitalized into property and equipment during fiscal 2016 .

LEASES

LEASES	12 Months Ended
	Dec. 26, 2018
Leases [Abstract]
LEASES	LEASES A summary of rent expense under operating lease agreements is as follows: 2018 2017 2016 Minimum rent $ 24,920 $ 20,421 $ 15,408 Deferred rent 1,241 838 2,122 Contingent rent 4,805 4,902 4,294 Total rent expense $ 30,966 $ 26,161 $ 21,824 The rent expense above does not include common area maintenance costs, real estate taxes and other occupancy costs, which were $6,479 , $4,570 and $3,229 in fiscal 2018 , 2017 and 2016 , respectively. As of December 26, 2018 , future minimum lease payments under non-cancelable operating leases and lease financing arrangements consisted of the following: Operating Leases Deemed Landlord Financing (1) 2019 $ 31,785 $ 4,487 2020 32,819 4,755 2021 33,363 4,816 2022 33,934 4,889 2023 33,588 5,085 Thereafter 174,145 22,659 Total minimum lease payments $ 339,634 $ 46,691 (1) Amounts include minimum lease payments for one lease under construction as of December 26, 2018 where we are deemed the accounting owner. Final classification of lease payments under deemed landlord financing is subject to change pending sale lease-back analysis performed at the store opening date. As of December 26, 2018 , we had 24 leases where we are involved in the construction of the leased assets and have been deemed the accounting owner of the construction project. The deemed landlord financing liability related to these leases was $20,846 as of December 26, 2018 . As of December 27, 2017 , we had 23 leases where we are involved in the construction of the leased assets and have been deemed the accounting owner of the construction project. The deemed landlord financing liability related to those leases was $14,518 as of December 27, 2017 .

EMPLOYEE BENEFIT PLANS

EMPLOYEE BENEFIT PLANS	12 Months Ended
	Dec. 26, 2018
Compensation Related Costs [Abstract]
EMPLOYEE BENEFIT PLANS	EMPLOYEE BENEFIT PLANS Deferred Compensation In fiscal 2014, we entered into an incentive bonus agreement with one of our executives, whereby the executive is entitled to receive a deferred compensation award in the amount of $2,450 payable by us in March 2018. This amount was included in other current liabilities on the Consolidated Balance Sheet as of December 27, 2017 . In fiscal 2013, we recorded $2,054 of deferred compensation expense to recognize the present value of the incentive bonus liability, which was included within general and administrative expense on the Consolidated Statement of Income (Loss). There was no such expense in fiscal 2018 , 2017 or 2016 . The difference between the present value of the bonus liability and the amount payable was accreted to interest expense over the term of the agreement. For the purpose of funding our deferred compensation obligation, we established a grantor trust, commonly referred to as a "rabbi trust," and contributed $2,450 to the trust in October 2015. Assets held by the trust were subject to creditor claims. In March 2018, we paid the entire incentive bonus of $2,450 to our executive from the trust. No amounts were held in the trust or payable by us as of December 26, 2018 . Defined Contribution Plan Our employees are eligible to participate in a defined contribution savings plan maintained by Union Square Hospitality Group, LLC, a related party. The plan is funded by employee and employer contributions. We pay our share of the employer contributions directly to the third party trustee. Employer contributions to the plan are at our discretion. Effective January 2014, we began making contributions matching a portion of participants' contributions. We match 100% of participants' contributions for the first 3% of eligible compensation contributed and 50% of contributions made in excess of 3% of eligible compensation up to 5% of eligible compensation. Employer contributions totaled $509 , $389 and $257 for fiscal 2018 , 2017 and 2016 , respectively.

STOCKHOLDER'S EQUITY

STOCKHOLDER'S EQUITY	12 Months Ended
	Dec. 26, 2018
Equity [Abstract]
STOCKHOLDER'S EQUITY	STOCKHOLDERS' EQUITY Redemptions of LLC Interests The SSE Holdings LLC Agreement provides that holders of LLC Interests may, from time to time, require SSE Holdings to redeem all or a portion of their LLC Interests for newly-issued shares of Class A common stock on a one-for-one basis. In connection with any redemption or exchange, we receive a corresponding number of LLC Interests, increasing our total ownership interest in SSE Holdings. During fiscal 2018 , an aggregate of 2,692,660 LLC Interests were redeemed by the non-controlling interest holders. Pursuant to the SSE Holdings LLC Agreement, we issued 2,692,660 shares of Class A common stock in connection with these redemptions and received 2,692,660 LLC Interests, increasing our ownership interest in SSE Holdings. Simultaneously, and in connection with these redemptions, 2,692,660 shares of Class B common stock were surrendered and cancelled. During fiscal 2017 , an aggregate of 1,003,585 LLC Interests were redeemed by the non-controlling interest holders. Pursuant to the SSE Holdings LLC Agreement, we issued 1,003,585 shares of Class A common stock in connection with these redemptions and received 1,003,585 LLC Interests, increasing our ownership interest in SSE Holdings. Simultaneously, and in connection with these redemptions, 1,003,585 shares of Class B common stock were surrendered and cancelled. Stock Compensation Plan Activity We received an aggregate of 300,696 and 372,508 LLC Interests in connection with the activity under our stock compensation plan during fiscal 2018 and 2017 , respectively. Dividend Restrictions We are a holding company with no direct operations. As a result, our ability to pay cash dividends on our common stock, if any, is dependent upon cash dividends, distributions or other transfers from SSE Holdings. The amounts available to us to pay cash dividends are subject to certain covenants and restrictions set forth in the Revolving Credit Facility. As of December 26, 2018 , essentially all of the net assets of SSE Holdings were restricted. See Note 9 for more information regarding the covenants and restrictions set forth in the Revolving Credit Facility.

NON-CONTROLLING INTERESTS

NON-CONTROLLING INTERESTS	12 Months Ended
	Dec. 26, 2018
Noncontrolling Interest [Abstract]
NON-CONTROLLING INTERESTS	NON-CONTROLLING INTERESTS We are the sole managing member of SSE Holdings and, as a result, consolidate the financial results of SSE Holdings. We report a non-controlling interest representing the economic interest in SSE Holdings held by the other members of SSE Holdings. The SSE Holdings LLC Agreement provides that holders of LLC Interests may, from time to time, require SSE Holdings to redeem all or a portion of their LLC Interests for newly-issued shares of Class A common stock on a one -for-one basis. In connection with any redemption or exchange, we will receive a corresponding number of LLC Interests, increasing our total ownership interest in SSE Holdings. Changes in our ownership interest in SSE Holdings while we retain our controlling interest in SSE Holdings will be accounted for as equity transactions. As such, future redemptions or direct exchanges of LLC Interests in SSE Holdings by the other members of SSE Holdings will result in a change in ownership and reduce the amount recorded as non-controlling interest and increase additional paid-in capital. The following table summarizes the ownership interest in SSE Holdings as of December 26, 2018 and December 27, 2017 : 2018 2017 LLC Interests Ownership % LLC Interests Ownership % Number of LLC Interests held by Shake Shack Inc. 29,520,833 79.6 % 26,527,477 72.1 % Number of LLC Interests held by non-controlling interest holders 7,557,347 20.4 % 10,250,007 27.9 % Total LLC Interests outstanding 37,078,180 100.0 % 36,777,484 100.0 % The weighted average ownership percentages for the applicable reporting periods are used to attribute net income and other comprehensive loss between Shake Shack Inc. and the non-controlling interest holders. The non-controlling interest holders' weighted average ownership percentage for fiscal 2018 and 2017 was 23.4% and 29.4% , respectively. The following table summarizes the effects of changes in ownership in SSE Holdings on our equity during fiscal 2018 , 2017 and 2016 . 2018 2017 2016 Net income (loss) attributable to Shake Shack Inc. $ 15,179 $ (320 ) $ 12,446 Other comprehensive income (loss): Unrealized holding gains (losses) on available-for-sale securities 10 (34 ) (10 ) Transfers (to) from non-controlling interests: Increase in additional paid-in capital as a result of the redemption of LLC Interests 15,202 4,415 16,986 Increase in additional paid-in capital as a result of activity under the stock compensation plan and the related income tax effect 2,509 4,451 825 Total effect of changes in ownership interest on equity attributable to Shake Shack Inc. $ 32,900 $ 8,512 $ 30,247 During fiscal 2018 , an aggregate of 2,692,660 LLC Interests were redeemed by the non-controlling interest holders for newly-issued shares of Class A common stock, and we received 2,692,660 LLC Interests, increasing our total ownership interest in SSE Holdings to 79.6% . During 2017 , an aggregate of 1,003,585 LLC Interests were redeemed by the non-controlling interest holders, and we received 1,003,585 LLC Interests, increasing our total ownership interest in SSE Holdings to 72.1% . We received an aggregate of 300,696 and 372,508 LLC Interests in connection with the activity under our stock compensation plans during fiscal 2018 and 2017 , respectively.

EQUITY-BASED COMPENSATION

EQUITY-BASED COMPENSATION	12 Months Ended
	Dec. 26, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
EQUITY-BASED COMPENSATION	EQUITY-BASED COMPENSATION A summary of equity-based compensation expense recognized during fiscal 2018 , 2017 and 2016 is as follows: 2018 2017 2016 Stock options 3,039 3,474 4,262 Performance stock units 2,449 1,869 1,092 Restricted stock units 655 280 — Equity-based compensation expense $ 6,143 $ 5,623 $ 5,354 Total income tax benefit recognized related to equity-based compensation $ 172 $ 198 $ 168 Equity-based compensation expense is allocated to general and administrative expenses and labor and related expenses on the Consolidated Statements of Income (Loss) during fiscal 2018 , 2017 and 2016 as follows: 2018 2017 2016 General and administrative expenses 5,991 5,463 5,260 Labor and related expenses 152 160 94 Equity-based compensation expense 6,143 5,623 5,354 We capitalized $107 , $109 and $139 of equity-based compensation expense associated with the construction cost of our Shacks and our enterprise-wide system upgrade initiative, Project Concrete, during fiscal 2018 , 2017 and 2016 , respectively. Stock Options In January 2015, we adopted the 2015 Incentive Award Plan (the "2015 Plan") under which we may grant up to 5,865,522 stock options and other equity-based awards to employees, directors and officers. The stock options granted generally vest equally over periods ranging from one to five years. We do not use cash to settle any of our equity-based awards, and we issue new shares of Class A common stock upon the exercise of stock options. The fair value of stock option awards was determined on the grant date using the Black-Scholes valuation model based on the following weighted-average assumptions: 2018 2017 2016 Expected term (years) (1) 7.5 7.5 5.5 Expected volatility (2) 42.5 % 44.5 % 50.7 % Risk-free interest rate (3) 2.8 % 2.1 % 1.5 % Dividend yield (4) — % — % — % (1) Expected term represents the estimated period of time until an award is exercised and was determined using the simplified method. (2) Expected volatility is based on the historical volatility of a selected peer group over a period equivalent to the expected term. (3) The risk-free rate rate is an interpolation of yields on U.S. Treasury securities with maturities equivalent to the expected term. (4) We have assumed a dividend yield of zero as we have no plans to declare dividends in the foreseeable future. A summary of stock option activity for fiscal years 2018 , 2017 and 2016 is as follows: Stock Options Weighted Average Exercise Price Aggregate Intrinsic Value Weighted Average Remaining Contractual Life (Years) Outstanding as of December 30, 2015 2,574,981 $ 21.00 Granted 16,931 34.74 Exercised (160,230 ) 21.00 Forfeited (66,960 ) (21.00 ) Expired — — Outstanding as of December 28, 2016 2,364,722 $ 21.10 Granted 5,150 38.91 Exercised (359,011 ) 21.13 Forfeited (291,520 ) (21.00 ) Expired — — Outstanding as of December 27, 2017 1,719,341 $ 21.16 Granted 5,036 39.91 Exercised (260,515 ) 21.00 Forfeited (102,879 ) (21.27 ) Expired — — Outstanding as of December 26, 2018 1,360,983 $ 21.25 $ 29,881 6.1 Options vested and exercisable as of December 26, 2018 674,247 $ 21.26 $ 14,798 6.1 Options expected to vest as of December 26, 2018 686,736 $ 21.25 $ 15,083 6.1 As of December 26, 2018 , total unrecognized compensation expense related to unvested stock options was $3,335 , which is expected to be recognized over a weighted-average period of 1.2 years. The total intrinsic value of stock options exercised during fiscal 2018 , 2017 and 2016 was $5,786 , $8,333 and $2,536 , respectively. C ash received from stock option exercises was $5,472 for fiscal 2018 . A summary of unvested stock option activity for fiscal years 2018 , 2017 and 2016 is as follows: Stock Options Weighted Average Grant-Date Fair Value Unvested as of December 30, 2015 2,574,981 $ 8.53 Vested (562,296 ) 8.32 Granted 16,931 16.32 Forfeited (65,365 ) 8.59 Unvested as of December 28, 2016 1,964,251 $ 8.66 Vested (503,686 ) 8.85 Granted 5,150 19.42 Forfeited (289,620 ) 8.59 Unvested as of December 27, 2017 1,176,095 $ 8.64 Vested (404,120 ) 8.62 Granted 5,036 19.86 Forfeited (90,275 ) 8.59 Unvested as of December 26, 2018 686,736 $ 8.74 The total fair value of stock options vested during fiscal 2018 , 2017 and 2016 was $3,483 , $4,458 and $4,678 , respectively. The following table summarizes information about stock options outstanding and exercisable as December 26, 2018 : Options Outstanding Options Exercisable Number Outstanding at December 26, 2018 Weighted Average Remaining Contractual Life (Years) Weighted Average Exercise Price Number Exercisable at December 26, 2018 Weighted Average Remaining Contractual Life (Years) Weighted Average Exercise Price Exercise Price $21.00 1,339,274 6.1 $ 21.00 661,694 6.1 $ 21.00 $34.62 10,415 7.4 $ 34.62 10,415 7.4 $ 34.62 $36.41 1,108 7.9 $ 36.41 1,108 7.9 $ 36.41 $38.91 5,150 8.5 $ 38.91 1,030 8.5 $ 38.91 $39.91 5,036 9.2 $ 39.91 — — $ — Performance Stock Units Under the 2015 Plan, we may grant performance stock units and other types of performance-based equity awards that vest based on the outcome of certain performance criteria that are established and approved by the Compensation Committee of the Board of Directors. The actual number of equity awards earned is based on the level of performance achieved over a predetermined performance period, relative to established financial goals, none of which are considered market conditions. For performance stock units granted during fiscal 2018 , the amount of awards that can be earned ranges from 0% to 125% of the number of performance stock units granted, based on the achievement of approved financial goals over a one -year performance period. In addition to the performance conditions, performance stock units are also subject to a requisite service period and the awards vest ratably over three years. The fair value of performance stock units is determined based on the closing market price of our Class A common stock on the date of grant. Compensation expense related to the performance stock units is recognized using a graded-vesting attribution method over the vesting period based on the most probable outcome of the performance conditions. A summary of performance stock unit activity for fiscal years 2018 , 2017 and 2016 is as follows: Performance Stock Units Weighted Average Grant Date Fair Value Outstanding as of December 30, 2015 — $ — Granted 63,600 38.41 Performance achievement (1) — — Vested — — Forfeited (2,000 ) 38.43 Expired — — Outstanding as of December 28, 2016 61,600 $ 38.41 Granted 87,596 37.90 Performance achievement (1) 9,545 38.40 Vested (22,703 ) 38.40 Forfeited (11,196 ) 38.28 Expired — — Outstanding as of December 27, 2017 124,842 $ 38.06 Granted 60,437 58.46 Performance achievement (1) (12,139 ) 37.89 Vested (43,861 ) 38.13 Forfeited (10,737 ) 41.28 Expired — — Outstanding as of December 26, 2018 118,542 $ 48.16 (1) Represents the incremental awards earned and/or awards forfeited based on the achievement of performance conditions. As of December 26, 2018 , there were 118,542 performance stock units outstanding, of which none were vested. As of December 26, 2018 , total unrecognized compensation expense related to unvested performance stock units was $2,954 , which is expected to be recognized over a weighted-average period of 2.2 years. Restricted Stock Units Under the 2015 Plan, we may grant restricted stock units to employees, directors and officers. The restricted stock units granted generally vest equally over periods ranging from one to five years. T he fair value of restricted stock units is determined based on the closing market price of our Class A common stock on the date of grant. Compensation expense related to the restricted stock units is recognized using a straight-line attribution method over the vesting period. A summary of restricted stock unit activity for fiscal years 2018 and 2017 is as follows: Restricted Stock Units Weighted Average Grant Date Fair Value Outstanding as of December 28, 2016 — $ — Granted 44,476 38.98 Vested — — Forfeited — — Expired — — Outstanding as of December 27, 2017 44,476 $ 38.98 Granted 18,882 49.12 Vested (13,635 ) 39.13 Forfeited — — Expired — — Outstanding as of December 26, 2018 49,723 $ 42.79 As of December 26, 2018 , there were 49,723 restricted stock units outstanding, of which none were vested. No restricted stock units were granted in fiscal 2016 . As of December 26, 2018 , total unrecognized compensation expense related to unvested restricted stock units was $1,726 , which is expected to be recognized over a weighted-average period of 3.5 years.

INCOME TAXES

INCOME TAXES	12 Months Ended
	Dec. 26, 2018
Income Tax Disclosure [Abstract]
INCOME TAXES	INCOME TAXES We are the sole managing member of SSE Holdings, and as a result, consolidate the financial results of SSE Holdings. SSE Holdings is treated as a partnership for U.S. federal and most applicable state and local income tax purposes. As a partnership, SSE Holdings is not subject to U.S. federal and certain state and local income taxes. Any taxable income or loss generated by SSE Holdings is passed through to and included in the taxable income or loss of its members, including us, on a pro rata basis. We are subject to U.S. federal income taxes, in addition to state and local income taxes with respect to our allocable share of any taxable income or loss of SSE Holdings, as well as any stand-alone income or loss generated by Shake Shack Inc. We are also subject to withholding taxes in foreign jurisdictions. Income Tax Expense The components of income before income taxes are follows: 2018 2017 2016 Domestic $ 21,595 $ 152,204 $ 20,623 Foreign 9,215 8,089 7,873 Income before income taxes $ 30,810 $ 160,293 $ 28,496 The components of income tax expense are as follows: 2018 2017 2016 Current income taxes: Federal $ 5,281 $ 518 $ 3,767 State and local 858 3,615 2,439 Foreign 1,935 942 667 Total current income taxes 8,074 5,075 6,873 Deferred income taxes: Federal (210 ) 145,139 (48 ) State and local 998 1,195 (475 ) Total deferred income taxes 788 146,334 (523 ) Income tax expense $ 8,862 $ 151,409 $ 6,350 Reconciliations of income tax expense computed at the U.S. federal statutory income tax rate to the recognized income tax expense and the U.S. statutory income tax rate to our effective tax rates are as follows: 2018 2017 2016 Expected U.S. federal income taxes at statutory rate $ 6,470 21.0 % $ 56,103 35.0 % $ 9,689 34.0 % State and local income taxes, net of federal benefit 797 2.6 % 2,590 1.6 % 1,461 5.1 % Foreign withholding taxes 1,935 6.3 % 942 0.6 % 667 2.3 % Tax credits (2,151 ) (7.0 )% (1,230 ) (0.8 )% (779 ) (2.7 )% Non-controlling interest (1,908 ) (6.2 )% (3,273 ) (2.0 )% (3,765 ) (13.2 )% Remeasurement of deferred tax assets in connection with the enactment of the TCJA — — % 138,636 86.5 % — — % Remeasurement of deferred tax assets in connection with other tax rate changes 3,794 12.3 % 1,657 1.0 % (1,353 ) (4.7 )% Remeasurement of liabilities under tax receivable agreement in connection with the enactment of the TCJA — — % (44,051 ) (27.4 )% — — % Other (75 ) (0.2 )% 35 — % 430 1.5 % Income tax expense $ 8,862 28.8 % $ 151,409 94.5 % $ 6,350 22.3 % Our effective income tax rates for fiscal 2018 , 2017 and 2016 were 28.8% , 94.5% and 22.3% , respectively. The decrease in our effective income tax rate from fiscal 2017 to fiscal 2018 and the increase from fiscal 2016 to fiscal 2017 were primarily due to the remeasurement of deferred tax assets resulting from the enactment of the Tax Cuts and Jobs Act of 2017 (the "TCJA") in fiscal 2017. In December 2017, the TCJA was enacted into law and provided for significant changes to the U.S. Internal Revenue Code of 1986, as amended, including the reduction of the U.S. federal corporate income tax rate from 35% to 21%, among other provisions. We calculated our best estimate of the impact of the TCJA based on current interpretations and understanding of the TCJA and recognized an additional $138,636 of income tax expense in fiscal 2017, in accordance with Staff Accounting Bulletin No. 118 ("SAB 118"), relating to the remeasurement of our deferred tax assets. During fiscal 2018 the Company finalized its calculations related to the impacts of the TCJA with no adjustment to the Company’s previously recorded provisional tax expense. Deferred Tax Assets and Liabilities The components of deferred tax assets and liabilities are as follows: December 26 December 27 Deferred tax assets: Investment in partnership $ 168,451 $ 137,449 Tax Receivable Agreement 57,203 43,464 Deferred rent 1,109 571 Deferred revenue 184 59 Stock-based compensation 375 322 Net operating loss carryforwards 18,046 12,332 Tax credits 5,194 2,328 Other assets 331 176 Total gross deferred tax assets 250,893 196,701 Valuation allowance (6,925 ) (10,114 ) Total deferred tax assets, net of valuation allowance 243,968 186,587 Deferred tax liabilities: Property and equipment (1,435 ) (673 ) Total gross deferred tax liabilities (1,435 ) (673 ) Net deferred tax assets $ 242,533 $ 185,914 As of December 26, 2018 , our federal and state net operating loss carryforwards for income tax purposes were $68,658 and $60,546 . If not utilized, $16,791 of our federal net operating losses can be carried forward indefinitely, and the remainder will begin to expire in 2035. If not utilized $4,586 of our state net operating loss carryforwards can be carried forward indefinitely, and the remainder will begin to expire in 2027. As described in Note 12, we acquired an aggregate of 2,993,356 LLC Interests during fiscal 2018 through redemptions of LLC Interests and activity under stock-based compensation plans. We recognized a deferred tax asset in the amount of $38,843 associated with the basis difference in our investment in SSE Holdings upon acquiring these LLC Interests. As of December 26, 2018 , the total deferred tax asset related to the basis difference in our investment in SSE Holdings was $168,451 . These were partially offset by reductions in basis due to the utilization of $12,383 of amortization. However, a portion of the total basis difference will only reverse upon the eventual sale of our interest in SSE Holdings, which we expect would result in a capital loss. As of December 26, 2018 , we established a valuation allowance in the amount of $6,192 against the deferred tax asset to which this portion relates. During fiscal 2018 , we also recognized $12,495 of deferred tax assets related to additional tax basis increases generated from expected future payments under the Tax Receivable Agreement and related deductions for imputed interest on such payments. See "—Tax Receivable Agreement" for more information. We evaluate the realizability of our deferred tax assets on a quarterly basis and establish valuation allowances when it is more likely than not that all or a portion of a deferred tax asset may not be realized. As of December 26, 2018 , we concluded, based on the weight of all available positive and negative evidence, that all of our deferred tax assets (except for those deferred tax assets described above relating to basis differences that are expected to result in a capital loss upon the eventual sale of our interest in SSE Holdings) are more likely than not to be realized, except for certain credits we no longer expect to utilize before expiration. As such, a valuation allowance in the amount of $733 was recognized. The net change in valuation allowance for fiscal 2018 was a decrease of $3,189 . Uncertain Tax Positions There were no reserves for uncertain tax positions as of December 26, 2018 and December 27, 2017 . Shake Shack Inc. was formed in September 2014 and did not engage in any operations prior to the IPO and Organizational Transactions. Shake Shack Inc. first filed tax returns for tax year 2014, which is the first tax year subject to examination by taxing authorities for U.S. federal and state income tax purposes. Additionally, although SSE Holdings is treated as a partnership for U.S. federal and state income taxes purposes, it is still required to file an annual U.S. Return of Partnership Income, which is subject to examination by the Internal Revenue Service ("IRS"). The statute of limitations has expired for tax years through 2014 for SSE Holdings. Tax Receivable Agreement Pursuant to our election under Section 754 of the Internal Revenue Code (the "Code"), we expect to obtain an increase in our share of the tax basis in the net assets of SSE Holdings when LLC Interests are redeemed or exchanged by the non-controlling interest holders and other qualifying transactions. We plan to make an election under Section 754 of Code for each taxable year in which a redemption or exchange of LLC Interest occurs. We intend to treat any redemptions and exchanges of LLC Interests by the non-controlling interest holders as direct purchases of LLC Interests for U.S. federal income tax purposes. These increases in tax basis may reduce the amounts that we would otherwise pay in the future to various tax authorities. They may also decrease gains (or increase losses) on future dispositions of certain capital assets to the extent tax basis is allocated to those capital assets. On February 4, 2015, we entered into a tax receivable agreement with the then-existing non-controlling interest holders (the "Tax Receivable Agreement") that provides for the payment by us to the non-controlling interest holders of 85% of the amount of any tax benefits that we actually realize, or in some cases are deemed to realize, as a result of (i) increases in our share of the tax basis in the net assets of SSE Holdings resulting from any redemptions or exchanges of LLC Interests, (ii) tax basis increases attributable to payments made under the Tax Receivable Agreement, and (iii) deductions attributable to imputed interest pursuant to the Tax Receivable Agreement (the "TRA Payments"). We expect to benefit from the remaining 15% of any tax benefits that we may actually realize. The TRA Payments are not conditioned upon any continued ownership interest in SSE Holdings or us. The rights of each non-controlling interest holder under the Tax Receivable Agreement are assignable to transferees of its LLC Interests. During fiscal 2018 , we acquired an aggregate of 2,692,660 LLC Interests in connection with the redemption of LLC Interests, which resulted in an increase in the tax basis of our investment in SSE Holdings subject to the provisions of the Tax Receivable Agreement. We recognized an additional liability in the amount of $44,338 for the TRA Payments due to the redeeming members, representing 85% of the aggregate tax benefits we expect to realize from the tax basis increases related to the redemption of LLC Interests, after concluding it was probable that such TRA Payments would be paid based on our estimates of future taxable income. No payments were made to members of SSE Holdings pursuant to the Tax Receivable Agreement during fiscal 2018 . As of December 26, 2018 , the total amount of TRA Payments due under the Tax Receivable Agreement was $203,725 , of which $5,804 was included in other current liabilities on the Consolidated Balance Sheet. See Note 18 for more information relating to our liabilities under the Tax Receivable Agreement.

EARNINGS PER SHARE

EARNINGS PER SHARE	12 Months Ended
	Dec. 26, 2018
Earnings Per Share [Abstract]
EARNINGS PER SHARE	EARNINGS PER SHARE Basic earnings per share of Class A common stock is computed by dividing net income attributable to Shake Shack Inc. by the weighted-average number of shares of Class A common stock outstanding during the period. Diluted earnings per share of Class A common stock is computed by dividing net income attributable to Shake Shack Inc. by the weighted-average number of shares of Class A common stock outstanding adjusted to give effect to potentially dilutive securities. The following table sets forth reconciliations of the numerators and denominators used to compute basic and diluted earnings per share of Class A common stock for fiscal 2018 , 2017 and 2016 . 2018 2017 2016 Numerator: Net income $ 21,948 $ 8,884 $ 22,146 Less: net income attributable to non-controlling interests 6,769 9,204 9,700 Net income (loss) attributable to Shake Shack Inc. $ 15,179 $ (320 ) $ 12,446 Denominator: Weighted-average shares of Class A common stock outstanding—basic 28,299 25,876 22,956 Effect of dilutive securities: Stock options 798 — 491 Performance stock units 63 — 2 Restricted stock units 19 — — Weighted-average shares of Class A common stock outstanding—diluted 29,179 25,876 23,449 Earnings (loss) per share of Class A common stock—basic $ 0.54 $ (0.01 ) $ 0.54 Earnings (loss) per share of Class A common stock—diluted $ 0.52 $ (0.01 ) $ 0.53 Shares of our Class B common stock do not share in the earnings or losses of Shake Shack and are therefore not participating securities. As such, separate presentation of basic and diluted earnings per share of Class B common stock under the two-class method has not been presented. The following table presents potentially dilutive securities excluded from the computations of diluted earnings per share of Class A common stock for fiscal 2018 , 2017 and 2016 . 2018 2017 2016 Stock options — 1,719,341 (2) 125 (1) Performance stock units 21,560 (3) 124,842 (2) 26,860 (3) Restricted stock units — 44,476 (2) — Shares of Class B common stock 7,557,347 (4) 10,250,007 (4) 11,253,592 (4) (1) Weighted-average number of securities excluded from the computation of diluted earnings per share of Class A common stock because the exercise price of the stock options exceeded the average market price of our Class A common stock during the period ("out-of-the-money"). (2) Represents number of instruments outstanding at the end of the period that were excluded from the computation of diluted earnings per share of Class A common stock because the effect would have been anti-dilutive. (3) Weighted-average number of securities excluded from the computation of diluted earnings per share of Class A common stock because the performance conditions were not met for a portion of the fiscal year. (4) Shares of our Class B common stock are considered potentially dilutive shares of Class A common stock. Amounts have been excluded from the computations of diluted earnings per share of Class A common stock because the effect would have been anti-dilutive under the if-converted and two-class methods.

SUPPLEMENTAL CASH FLOW INFORMAT

SUPPLEMENTAL CASH FLOW INFORMATION	12 Months Ended
	Dec. 26, 2018
Supplemental Cash Flow Elements [Abstract]
SUPPLEMENTAL CASH FLOW INFORMATION	SUPPLEMENTAL CASH FLOW INFORMATION The following table sets forth supplemental cash flow information for fiscal 2018 , 2017 and 2016 : 2018 2017 2016 Cash paid for: Income taxes, net of refunds $ 3,272 $ 2,261 $ 1,823 Interest, net of amounts capitalized 2,261 1,106 54 Non-cash investing activities: Accrued purchases of property and equipment 17,443 7,526 6,150 Capitalized landlord assets for leases where we are deemed the accounting owner 5,443 10,125 1,985 Capitalized equity-based compensation 107 109 139 Non-cash financing activities: Class A common stock issued in connection with the redemption of LLC Interests 2 1 5 Cancellation of Class B common stock in connection with the redemption of LLC Interests (2 ) (1 ) (5 ) Establishment of liabilities under tax receivable agreement 44,338 18,973 100,063 Accrued distributions payable to non-controlling interest holders — — 607

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	12 Months Ended
	Dec. 26, 2018
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES Lease Commitments We are obligated under various operating leases for Shacks and our Home Office space, expiring in various years through 2035 . Under certain of these leases, we are liable for contingent rent based on a percentage of sales in excess of specified thresholds and are responsible for our proportionate share of real estate taxes, common area maintenance charges and utilities. See Note 10 , Leases. As security under the terms of one of our leases, we are obligated under a letter of credit totaling $130 as of December 26, 2018 , which expires on February 28, 2026 . In addition, we entered into two irrevocable standby letters of credit: (i) in December 2013, we entered into a letter of credit in conjunction with our previous Home Office lease in the amount of $80 , which expires in September 2019 and (ii) in September 2017, we entered into a letter of credit in conjunction with our new Home Office lease in the amount of $603 , which expires in August 2019 and renews automatically for one-year periods through January 31, 2034 . Purchase Commitments Purchase obligations include legally binding contracts, including commitments for the purchase, construction or remodeling of real estate and facilities, firm minimum commitments for inventory purchases, equipment purchases, marketing-related contracts, software acquisition/license commitments and service contracts. These obligations are generally short-term in nature and are recorded as liabilities when the related goods are received or services rendered. We also enter into long-term, exclusive contracts with certain vendors to supply us with food, beverages and paper goods, obligating us to purchase specified quantities. These volume commitments are generally not subject to any time limit and there are no material financial penalties associated with these agreements in the event of early termination. Legal Contingencies In February 2018, a claim was filed against Shake Shack in California state court alleging certain violations of the California Labor Code. At a mediation between the parties, we agreed to settle the matter with the plaintiff and all other California employees who elect to participate in the settlement for $1,200 . As of December 26, 2018 , an accrual in the amount of $1,200 was recorded for this matter and related expenses. We are subject to various legal proceedings, claims and liabilities, such as employment-related claims and slip and fall cases, which arise in the ordinary course of business and are generally covered by insurance. As of December 26, 2018 , the amount of the ultimate liability with respect to these matters was not material. Liabilities under Tax Receivable Agreement As described in Note 15, we are a party to the Tax Receivable Agreement under which we are contractually committed to pay the non-controlling interest holders 85% of the amount of any tax benefits that we actually realize, or in some cases are deemed to realize, as a result of certain transactions. We are not obligated to make any payments under the Tax Receivable Agreement until the tax benefits associated the transaction that gave rise to the payment are realized. Amounts payable under the Tax Receivable Agreement are contingent upon, among other things, (i) generation of future taxable income over the term of the Tax Receivable Agreement and (ii) future changes in tax laws. If we do not generate sufficient taxable income in the aggregate over the term of the Tax Receivable Agreement to utilize the tax benefits, then we would not be required to make the related TRA Payments. As of December 26, 2018 , we recognized $203,725 of liabilities relating to our obligations under the Tax Receivable Agreement, after concluding that it was probable that we would have sufficient future taxable income to utilize the related tax benefits. There were no transactions subject to the Tax Receivable Agreement for which we did not recognize the related liability, as we concluded that we would have sufficient future taxable income to utilize all of the related tax benefits generated by all transactions that occurred in fiscal 2018 .

RELATED PARTY TRANSACTIONS

RELATED PARTY TRANSACTIONS	12 Months Ended
	Dec. 26, 2018
Related Party Transactions [Abstract]
RELATED PARTY TRANSACTIONS	RELATED PARTY TRANSACTIONS Union Square Hospitality Group The Chairman of our Board of Directors serves as the Chief Executive Officer of Union Square Hospitality Group, LLC. As a result, Union Square Hospitality Group, LLC and its subsidiaries are considered related parties. USHG, LLC Effective January 2015, we entered into an Amended and Restated Management Services Agreement with USHG, LLC ("USHG"), which USHG provides reduced management services to SSE Holdings comprised of executive leadership from members of its senior management, advisory and development services and limited leadership development and human resources services. The initial term of the Amended and Restated Management Services Agreement is through December 31, 2019, with renewal periods. Amounts paid to USHG for general corporate expenses were $2 , $7 and $10 for fiscal 2018 , 2017 and 2016 , respectively, and are included in general and administrative expenses on the Consolidated Statements of Income (Loss) . No amounts were payable to USHG as of December 26, 2018 and December 27, 2017 . No amounts were due from USHG as of December 26, 2018 and December 27, 2017 . Hudson Yards Sports and Entertainment In fiscal 2011, we entered into a Master License Agreement (as amended, an "MLA") with Hudson Yards Sports and Entertainment LLC ("HYSE") to operate Shake Shack branded limited menu concession stands in sports and entertainment venues within the United States. The agreement expires on December 31, 2027 and includes five consecutive five -year renewal options at HYSE's option. As consideration for these rights, HYSE pays us a license fee based on a percentage of net food sales, as defined in the MLA. HYSE also pays us a percentage of profits on sales of branded beverages, as defined in the MLA. Amounts paid to us by HYSE for fiscal 2018 , 2017 and 2016 were $420 , $452 and $309 , respectively, and are included in licensing revenue on the Consolidated Statements of Income (Loss) . Total amounts due from HYSE as of December 26, 2018 and December 27, 2017 were $37 and $18 , respectively, which are included in other current assets on the Consolidated Balance Sheets . Madison Square Park Conservancy The Chairman of our Board of Directors serves as a director of the Madison Square Park Conservancy ("MSP Conservancy"), with which we have a license agreement and pay license fees to operate our Madison Square Park Shack. Amounts paid to Madison Square Park Conservancy as rent amounted to $877 , $907 and $1,062 for f iscal 2018 , 2017 and 2016 , respectively. These amounts are included in occupancy and related expenses on the Consolidated Statements of Income (Loss) . Total amounts due to MSP Conservancy were $70 as of December 26, 2018 , which is included in accrued expenses on the Consolidated Balance Sheets. No amounts were due to MSP Conservancy as of December 27, 2017 . Additionally, we received tenant improvement allowances from MSP Conservancy related to a reconstruction project which ended in 2015. Amounts paid to us from MSP Conservancy for fiscal 2017 were $200 . No amounts were paid to us by MSP Conservancy in fiscal 2018 and 2016 . No amounts were due to us from MSP Conservancy as of December 26, 2018 and December 27, 2017 . Share Our Strength The Chairman of our Board of Directors serves as a director of Share Our Strength, for which Shake Shack holds the "Great American Shake Sale" every year during the month of May to raise money and awareness for childhood hunger. During the Great American Shake Sale, we encourage guests to donate money to Share Our Strength's No Kid Hungry campaign in exchange for a coupon for a free shake. All of the guest donations we collect go directly to Share Our Strength. We raised a total of $343 , $633 and $587 , in fiscal 2018 , 2017 and 2016 , respectively, and the proceeds were remitted to Share Our Strength in the respective years. We incurred costs of approximately $53 , $148 and $117 for fiscal 2018 , 2017 and 2016 , respectively, representing the cost of the free shakes redeemed. These costs are included in general and administrative expenses and other operating expenses on the Consolidated Statements of Income (Loss) . Additionally, we held a promotional event in August 2016 in which we donated a total of $20 to the Share Our Strength's No Kid Hungry campaign, which is included in general and administrative expenses on the Consolidated Statements of Income (Loss) . Mobo Systems, Inc. The Chairman of our Board of Directors serves as a director of Mobo Systems, Inc. (also known as "Olo"), a platform we use in connection with our kiosks and web and mobile ordering applications. Amounts paid to Olo for fiscal 2018 and 2017 were $111 and $80 , respectively, which are included in other operating expenses on the Consolidated Statements of Income (Loss) . No amounts were paid to Olo for fiscal 2016 . No amounts were payable to Olo as of December 26, 2018 and December 27, 2017 . Square, Inc. In July 2017, our Chief Executive Officer joined the Board of Directors of Square, Inc. ("Square"). We currently use certain point-of-sale applications, payment processing services, hardware and other enterprise platform services in connection with the processing of a limited amount of sales at certain of our Shacks, sales for certain off-site events and in connection with our kiosk technology. Additionally, we partnered with Caviar, Square’s food ordering service for delivery services, in a number of cities for limited-time delivery promotions. Tax Receivable Agreement In connection with our IPO, we entered into a Tax Receivable Agreement with certain non-controlling interest holders that provides for the payment by us to the non-controlling holders of 85% of the amount of any tax benefits that Shake Shack actually realizes or in some cases is deemed to realize as a result of (i) increases in the tax basis of the net assets of SSE Holdings resulting from any redemptions or exchanges of LLC Interests and (ii) certain other tax benefits related to our making payments under the Tax Receivable Agreement. See Note 15 for further information. In fiscal 2017 , payments of $4,910 , inclusive of interest, were made to the non-controlling interest holders. There were no amounts paid under the Tax Receivable Agreement to the non-controlling interest holders during fiscal 2018 and 2016 . As of December 26, 2018 and December 27, 2017 , total amounts due under the Tax Receivable Agreement were $203,725 and $159,373 , respectively. Distributions to Members of SSE Holdings Under the terms of the SSE Holdings LLC Agreement, SSE Holdings is obligated to make tax distributions to its members. During fiscal 2018 , 2017 and 2016 , tax distributions of $751 , $2,379 and $1,745 , respectively, were paid to non-controlling interest holders. No tax distributions were payable to non-controlling interest holders as of December 26, 2018 and December 27, 2017 .

GEOGRAPHIC INFORMATION

GEOGRAPHIC INFORMATION	12 Months Ended
	Dec. 26, 2018
Segment Reporting [Abstract]
GEOGRAPHIC INFORMATION	GEOGRAPHIC INFORMATION Revenue by geographic area for fiscal 2018 , 2017 and 2016 is as follows: 2018 2017 2016 United States $ 447,575 $ 348,575 $ 260,602 Other countries 11,735 10,235 7,873 Total revenue $ 459,310 $ 358,810 $ 268,475 Revenues are shown based on the geographic location of our customers and licensees. All of our assets are located in the United States.

SELECTED QUARTERLY FINANCIAL DA

SELECTED QUARTERLY FINANCIAL DATA (UNAUDITED)	12 Months Ended
	Dec. 26, 2018
Quarterly Financial Information Disclosure [Abstract]
SELECTED QUARTERLY FINANCIAL DATA (UNAUDITED)	SELECTED QUARTERLY FINANCIAL DATA (UNAUDITED) The following table sets forth certain unaudited financial information for each quarter of fiscal 2018 and 2017 . The unaudited quarterly information includes all adjustments (consisting of normal recurring adjustments) that, in the opinion of management, are necessary for the fair presentation of the information presented. Operating results for interim periods are not necessarily indicative of the results that may be expected for a full fiscal year. 2018 First Second Third Fourth Quarter Quarter Quarter Quarter Total revenue $ 99,116 $ 116,282 $ 119,647 $ 124,265 Operating income 6,514 13,018 9,343 2,836 Net income (loss) 4,979 10,571 6,946 (548 ) Net income (loss) attributable to Shake Shack Inc. 3,508 7,604 5,025 (958 ) Earnings (loss) per share (1) : Basic $ 0.13 $ 0.27 $ 0.17 $ (0.03 ) Diluted $ 0.13 $ 0.26 $ 0.17 $ (0.03 ) 2017 First Second Third Fourth Quarter Quarter Quarter Quarter Total revenue $ 76,749 $ 91,316 $ 94,609 $ 96,136 Operating income 5,628 11,737 10,610 5,838 Net income (loss) 3,682 8,184 7,870 (11,032 ) Net income (loss) attributable to Shake Shack Inc. 2,267 4,879 4,997 (12,463 ) Earnings (loss) per share (1) : Basic $ 0.09 $ 0.19 $ 0.19 $ (0.47 ) Diluted $ 0.09 $ 0.19 $ 0.19 $ (0.47 ) (1) Basic and diluted earnings per share are computed independently for each of the quarters presented. Therefore, the sum of quarterly basic and diluted earnings per share amounts may not equal annual basic and diluted earnings per share amounts.

SCHEDULE I_ CONDENSED FINANCIAL

SCHEDULE I: CONDENSED FINANCIAL INFORMATION OF REGISTRANT	12 Months Ended
	Dec. 26, 2018
Condensed Financial Information Disclosure [Abstract]
SCHEDULE I: CONDENSED FINANCIAL INFORMATION OF REGISTRANT	SHAKE SHACK INC. CONDENSED BALANCE SHEETS (PARENT COMPANY ONLY) (in thousands, except share and per share amounts) December 26 December 27 ASSETS Current assets: Cash $ 5,686 $ 4,988 Prepaid expenses 135 100 Total current assets 5,821 5,088 Deferred income taxes, net 242,353 185,750 Investment in subsidiaries 185,331 142,314 TOTAL ASSETS $ 433,505 $ 333,152 LIABILITIES AND STOCKHOLDERS' EQUITY Current liabilities: Accrued expenses 171 70 Due to SSE Holdings 3,534 4,217 Current portion of liabilities under tax receivable agreement 5,804 937 Total current liabilities 9,509 5,224 Liabilities under tax receivable agreement, net of current portion 197,921 158,436 Total liabilities 207,430 163,660 Commitments and contingencies Stockholders' equity: Preferred stock, no par value—10,000,000 shares authorized; none issued and outstanding as of December 26, 2018 and December 27, 2017, respectively. — — Class A common stock, $0.001 par value—200,000,000 shares authorized; 29,520,833 and 26,527,477 shares issued and outstanding as of December 26, 2018 and December 27, 2017, respectively. 30 27 Class B common stock, $0.001 par value—35,000,000 shares authorized; 7,557,347 and 10,250,007 shares issued and outstanding as of December 26, 2018 and December 27, 2017, respectively. 8 10 Additional paid-in capital 195,633 153,105 Retained earnings 30,404 16,399 Accumulated other comprehensive loss — (49 ) Total stockholders' equity 226,075 169,492 TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY $ 433,505 $ 333,152 See accompanying Notes to Condensed Financial Statements. SHAKE SHACK INC. CONDENSED STATEMENTS OF INCOME (LOSS) (PARENT COMPANY ONLY) (in thousands) Fiscal Year Ended December 26 December 27 December 28 Intercompany revenue $ 2,055 $ 1,466 $ 1,603 TOTAL REVENUE 2,055 1,466 1,603 General and administrative expenses 1,933 1,692 1,603 TOTAL EXPENSES 1,933 1,692 1,603 OPERATING INCOME (LOSS) 122 (226 ) — Equity in net income of subsidiaries 21,537 22,090 16,982 Other income 78 127,221 688 Interest expense (14 ) (50 ) (16 ) INCOME BEFORE INCOME TAXES 21,723 149,035 17,654 Income tax expense 6,544 149,355 5,208 NET INCOME (LOSS) $ 15,179 $ (320 ) $ 12,446 See accompanying Notes to Condensed Financial Statements. SHAKE SHACK INC. CONDENSED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (PARENT COMPANY ONLY) (in thousands) Fiscal Year Ended December 26 December 27 December 28 Net income (loss) $ 15,179 $ (320 ) $ 12,446 Other comprehensive income (loss), net of tax: Available-for-sale securities (1) : Change in net unrealized holding losses (3 ) (67 ) (22 ) Less: reclassification adjustments for net realized losses included in net income 13 33 12 Net change 10 (34 ) (10 ) OTHER COMPREHENSIVE INCOME (LOSS) 10 (34 ) (10 ) COMPREHENSIVE INCOME (LOSS) $ 15,189 $ (354 ) $ 12,436 (1) Net of tax benefit of $0 for fiscal years ended December 26, 2018 , December 27, 2017 and December 28, 2016 . See accompanying Notes to Condensed Financial Statements. SHAKE SHACK INC. CONDENSED STATEMENTS OF CASH FLOWS (PARENT COMPANY ONLY) (in thousands) Fiscal Year Ended December 26 December 27 December 28 OPERATING ACTIVITIES Net income (loss) $ 15,179 $ (320 ) $ 12,446 Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities: Equity in net income of subsidiaries (21,537 ) (22,090 ) (16,982 ) Equity-based compensation 252 234 189 Non-cash reimbursement revenue treated as investment — — (189 ) Deferred income taxes 777 146,095 (462 ) Other non-cash income (78 ) (127,221 ) (688 ) Changes in operating assets and liabilities: Accounts receivable — 2 (2 ) Prepaid expenses and other current assets — 5 (1 ) Due to/from SSE Holdings (7,103 ) (5,339 ) 214 Accrued expenses 5,669 21 (11 ) Other current liabilities 14 (17 ) 17 Income taxes payable — 2,990 5,023 NET CASH USED IN OPERATING ACTIVITIES (6,827 ) (5,640 ) (446 ) INVESTING ACTIVITIES Purchases of LLC Interests from SSE Holdings (11,142 ) (5,522 ) (4,559 ) Return of investment in SSE Holdings 2,053 4,101 2,694 NET CASH USED IN INVESTING ACTIVITIES (9,089 ) (1,421 ) (1,865 ) FINANCING ACTIVITIES Proceeds from issuance of Class A common stock to SSE Holdings upon settlement of equity awards 11,142 5,522 2,489 Proceeds from stock option exercises 5,472 7,586 3,185 Payments under tax receivable agreement — (4,844 ) — NET CASH PROVIDED BY FINANCING ACTIVITIES 16,614 8,264 5,674 INCREASE IN CASH 698 1,203 3,363 CASH AT BEGINNING OF PERIOD 4,988 3,785 422 CASH AT END OF PERIOD $ 5,686 $ 4,988 $ 3,785 See accompanying Notes to Condensed Financial Statements. NOTE 1: ORGANIZATION Sha ke Shack Inc. (the "Parent Company") was formed on September 23, 2014 as a Delaware corporation and is a holding company with no direct operations. The Parent Company's assets consist primarily of its equity interest in SSE Holdings, LLC ("SSE Holdings") and certain deferred tax assets. The Parent Company's cash inflows are primarily from cash dividends or distributions and other transfers from SSE Holdings. The amounts available to the Parent Company to fulfill cash commitments and pay cash dividends on its common stock are subject to certain restrictions in SSE Holdings' revolving credit agreement. See Note 9 to the consolidated financial statements. NOTE 2: BASIS OF PRESENTATION These condensed parent company financial statements should be read in conjunction with the consolidated financial statements of Shake Shack Inc. and the accompanying notes thereto, included in this Annual Report on Form 10-K. For purposes of these condensed financial statements, the Parent Company's interest in SSE Holdings is recorded based upon its proportionate share of SSE Holdings' net assets (similar to presenting them on the equity method). The Parent Company is the sole managing member of SSE Holdings, and pursuant to the Third Amended and Restated LLC Agreement of SSE Holdings (the “SSE Holdings LLC Agreement”), receives compensation in the form of reimbursements for all costs associated with being a public company and maintaining its existence. Intercompany revenue consists of these reimbursement payments and is recognized when the corresponding expense to which it relates is recognized. Certain intercompany balances presented in these condensed parent company financial statements are eliminated in the consolidated financial statements. As of December 26, 2018 , $3,534 of intercompany payables were eliminated in consolidation and $4,217 of intercompany payables were eliminated in consolidation as of December 27, 2017 . For fiscal 2018 , $2,055 and $21,537 of intercompany revenue and equity in net income of subsidiaries, respectively, was eliminated in consolidation. For fiscal 2017 , $1,466 and $22,090 of intercompany revenue and equity in net income of subsidiaries, respectively, was eliminated in consolidation. Related party amounts that were not eliminated in the consolidated financial statements include the Parent Company's liabilities under the tax receivable agreement, which totaled $203,725 and $159,373 as of December 26, 2018 and December 27, 2017 , respectively. NOTE 3: COMMITMENTS AND CONTINGENCIES On February 4, 2015, the Parent Company entered into a tax receivable agreement with the non-controlling interest holders that provides for payments to the non-controlling interest holders of 85% of the amount of any tax benefits that the Parent Company actually realizes, or in some cases is deemed to realize, as a result of certain transactions. S ee Note 15 to the consolidated financial statements for more information regarding the Parent Company's tax receivable agreement. As described in Note 18 to the consolidated financial statements, a mounts payable under the tax receivable agreement are contingent upon, among other things, (i) generation of future taxable income of Shake Shack Inc. over the term of the tax receivable agreement and (ii) future changes in tax laws. As of December 26, 2018 and December 27, 2017 , liabilities under the tax receivable agreement totaled $203,725 and $159,373 , respectively. NOTE 4: SUPPLEMENTAL CASH FLOW INFORMATION The following table sets forth supplemental cash flow information for fiscal 2018 , 2017 and 2016 : 2018 2017 2016 Cash paid for: Income taxes $ 185 $ 253 $ 576 Interest — 2 — Non-cash investing activities: Accrued contribution related to stock option exercises 5,472 7,586 1,116 Class A common stock issued in connection with the acquisition of LLC Interests upon redemption by the non-controlling interest holders 15,202 4,415 18,944 Non-cash contribution made in connection with equity awards granted to employees of SSE Holdings 5,999 5,497 5,304 Non-cash financing activities: Cancellation of Class B common stock in connection with the Organizational Transactions Cancellation of Class B common stock in connection with the redemption of LLC Interests (2 ) (1 ) (5 ) Establishment of liabilities under tax receivable agreement 44,338 18,973 100,063

SCHEDULE II_ VALUATION AND QUAL

SCHEDULE II: VALUATION AND QUALIFYING ACCOUNTS	12 Months Ended
	Dec. 26, 2018
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
SCHEDULE II: VALUATION AND QUALIFYING ACCOUNTS	Schedule II: Valuation and Qualifying Accounts Balance at beginning of period Additions Reductions Balance at end of period (in thousands) Charged to costs and expenses Charged to other accounts Deferred tax asset valuation allowance: Fiscal year ended December 31, 2014 $ — $ — $ — $ — $ — Fiscal year ended December 30, 2015 $ — $ — $ 39,700 (1) $ (16,545 ) $ 23,155 Fiscal year ended December 28, 2016 $ 23,155 $ 90 $ 1,965 (1) $ (9,642 ) $ 15,568 Fiscal year ended December 27, 2017 $ 15,568 $ — $ 3,455 (1) $ (8,909 ) (2) $ 10,114 Fiscal year ended December 26, 2018 $ 10,114 $ 782 $ — $ (3,971 ) $ 6,925 (1) Amount relates to a valuation allowance established on deferred tax assets related to our investment in SSE Holdings. (2) Amount includes a $4,780 remeasurement adjustment related to the enactment of the TCJA, which was recognized through earnings.

SUMMARY OF SIGNIFICANT ACCOUN_2

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	12 Months Ended
	Dec. 26, 2018
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) and include our accounts and the accounts of our subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation. Certain reclassifications have been made to prior period amounts to conform to the current year presentation. SSE Holdings is considered a variable interest entity. Shake Shack Inc. is the primary beneficiary as we have the majority economic interest in SSE Holdings and, as the sole managing member, have decision making authority that significantly affects the economic performance of the entity, while the limited partners have no substantive kick-out or participating rights. As a result, we will continue to consolidate SSE Holdings. The assets and liabilities of SSE Holdings represent substantially all of our consolidated assets and liabilities with the exception of certain deferred taxes and liabilities under the Tax Receivable Agreement. As of December 26, 2018 and December 27, 2017 , the net assets of SSE Holdings were $232,711 and $197,301 , respectively. The assets of SSE Holdings are subject to certain restrictions in SSE Holdings' revolving credit agreements. See Note 9 for more information.
Fiscal Year	Fiscal Year We operate on a 52/53 week fiscal year ending on the last Wednesday in December. Fiscal year 2018 contained 52 weeks and ended on December 26, 2018 . Fiscal year 2017 contained 52 weeks and ended on December 27, 2017 . Fiscal year 2016 contained 52 weeks and ended on December 28, 2016 . Unless otherwise stated, references to years in this report relate to fiscal years.
Use of Estimates	Use of Estimates The preparation of these consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of sales and expenses during the reporting period. Actual results could differ from those estimates.
Segment Reporting	Segment Reporting We own and operate Shacks in the United States. We also have domestic and international licensed operations. Our chief operating decision maker (the "CODM") is our Chief Executive Officer. As the CODM reviews financial performance and allocates resources at a consolidated level on a recurring basis, we have one operating segment and one reportable segment.
Fair Value Measurements	Fair Value Measurements We apply fair value accounting for all financial assets and liabilities and non-financial assets and liabilities that are recognized or disclosed at fair value in the financial statements on a recurring basis. Fair value is defined as the price that would be received from selling an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. When determining the fair value measurements for assets and liabilities that are required to be recorded at fair value, we assume the highest and best use of the asset by market participants in which we would transact and the market-based risk measurements or assumptions that market participants would use in pricing the asset or liability, such as inherent risk, transfer restrictions, and credit risk. Assets and liabilities are classified using a fair value hierarchy, which prioritizes the inputs used to measure fair value into three levels, and bases the categorization within the hierarchy upon the lowest level of input that is available and significant to the fair value measurement: ▪ Level 1 - Quoted prices in active markets for identical assets or liabilities ▪ Level 2 - Observable inputs other than quoted prices in active markets for identical assets or liabilities, quoted prices for identical assets or liabilities in inactive markets, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities ▪ Level 3 - Inputs that are both unobservable and significant to the overall fair value measurements reflecting an entity's estimates of assumptions that market participants would use in pricing the asset or liability
Cash and Cash Equivalents	Cash and Cash Equivalents Cash and cash equivalents consist primarily of cash on hand, deposits with banks, and short-term, highly liquid investments that have original maturities of three months or less. Cash equivalents are stated at cost, which approximates fair value. Cash equivalents consist primarily of money market funds.
Accounts Receivable	Accounts Receivable Accounts receivable consist primarily of receivables from landlords for tenant improvement allowances, receivables from our licensees for licensing revenue and related reimbursements, credit card receivables and vendor rebates. We evaluate the collectibility of our accounts receivable based on a variety of factors, including historical experience, current economic conditions and other factors.
Inventories	Inventories Inventories, which consist of food, beer, wine, other beverages and retail merchandise, are stated at the lower of cost or net realizable value with cost determined on a first-in, first-out basis. No adjustment is deemed necessary to reduce inventory to net realizable value due to the rapid turnover and high utilization of inventory.
Property and Equipment	Property and Equipment Property and equipment is stated at historical cost less accumulated depreciation. Property and equipment is depreciated based on the straight-line method over the estimated useful lives of the assets, generally ranging from three to seven years for equipment, furniture and fixtures, and computer equipment and software. Leasehold improvements are depreciated over the shorter of their estimated useful life or the related lease life, generally ranging from 10 to 15 years. Landlord funded assets are depreciated over the shorter of their estimated useful life or the related lease life, generally ranging from 10 to 15 years. For leases with renewal periods at our option, we use the original lease term, excluding renewal option periods, to determine estimated useful lives. Costs incurred when constructing Shacks are capitalized. The cost of repairs and maintenance are expensed when incurred. Costs for refurbishments and improvements that significantly increase the productive capacity or extend the useful life of the asset are capitalized. When assets are disposed of, the resulting gain or loss is recognized on the Consolidated Statements of Income (Loss). We assess potential impairments to our long-lived assets, which includes property and equipment, whenever events or circumstances indicate that the carrying amount of an asset may not be recoverable. Recoverability of an asset is measured by a comparison of the carrying amount of an asset group to its estimated undiscounted future cash flows expected to be generated by the asset. If the carrying amount of the asset group exceeds its estimated undiscounted future cash flows, an impairment charge is recognized as the amount by which the carrying amount of the asset exceeds the fair value of the asset.
Deferred Financing Costs	Deferred Financing Costs Deferred financing costs incurred in connection with the issuance of long-term debt and establishing credit facilities are capitalized and amortized to interest expense based on the related debt agreements. Deferred financing costs are included in other assets on the Consolidated Balance Sheets.
Other Assets	Other Assets Other assets consist primarily of capitalized implementation costs from cloud computing arrangements, long-term marketable securities, security deposits, transferable liquor licenses and certain custom furniture pre-ordered for future Shacks and yet to be placed in service. The costs of obtaining non-transferable liquor licenses that are directly issued by local government agencies for nominal fees are expensed as incurred. The costs of purchasing transferable liquor licenses through open markets in jurisdictions with a limited number of authorized liquor licenses are capitalized as indefinite-lived intangible assets. Annual liquor license renewal fees are expensed over the renewal term. As of December 26, 2018 and December 27, 2017 , indefinite-lived intangible assets relating to transferable liquor licenses totaled $1,159 and $894 , respectively. We evaluate our indefinite-lived intangible assets for impairment annually during our fiscal fourth quarter, and whenever events or changes in circumstances indicate that an impairment may exist. When evaluating other intangible assets for impairment, we may first perform a qualitative assessment to determine whether it is more likely than not that an intangible asset group is impaired. If we do not perform the qualitative assessment, or if we determine that it is not more likely than not that the fair value of the intangible asset group exceeds its carrying amount, we calculate the estimated fair value of the intangible asset group. If the carrying amount of the intangible asset group exceeds the estimated fair value, an impairment charge is recorded to reduce the carrying value to the estimated fair value. In addition, we continuously monitor and may revise our intangible asset useful lives if and when facts and circumstances change.
Equity-based Compensation	Equity-based Compensation Equity-based compensation expense is measured based on fair value. For awards with graded-vesting features and service conditions only, compensation expense is recognized on a straight-line basis over the total requisite service period for the entire award. For awards with graded-vesting features and a combination of service and performance conditions, compensation expense is recognized using a graded-vesting attribution method over the vesting period based on the most probable outcome of the performance conditions. Forfeitures are recognized as they occur for all equity awards. Equity-based compensation expense is included within general and administrative expenses and labor and related expenses on the Consolidated Statements of Income (Loss) .
Leases	Leases We lease all of our domestic company-operated Shacks, our Home Office and certain equipment under various non-cancelable lease agreements that expire on various dates through 2035. Generally, our real estate leases have initial terms ranging from 10 to 15 years and typically include two five -year renewal options. At the inception of each lease, we determine its classification as an operating or capital lease. Most of our leases are classified as operating leases and typically provide for fixed minimum rent payments and/or contingent rent payments based upon sales in excess of specified thresholds. When the achievement of such sales thresholds are deemed to be probable, contingent rent is accrued in proportion to the sales recognized during the period. For operating leases that include rent holidays and rent escalation clauses, we recognize rent expense on a straight-line basis over the lease term from the date we take possession of the leased property. The difference between the straight-line rent amounts and amounts payable under the lease agreements is recorded as deferred rent and is included as rent expense in occupancy and related expenses on the Consolidated Statements of Income (Loss) . Rent expense incurred before a Shack opens is recorded in pre-opening costs. Once a domestic company-operated Shack opens, we record the straight-line rent expense and any contingent rent, if applicable, in occupancy and related expenses on the Consolidated Statements of Income (Loss) . Many of our leases also require us to pay real estate taxes, common area maintenance costs and other occupancy costs which are included in occupancy and related expenses on the Consolidated Statements of Income (Loss) . We expend cash for leasehold improvements to build out and equip our leased premises. Generally, a portion of the leasehold improvements and building costs are reimbursed by our landlords as landlord incentives pursuant to agreed-upon terms in our lease agreements. If obtained, landlord incentives usually take the form of up-front cash, full or partial credits against our future minimum or contingent rents otherwise payable by us, or a combination thereof. When contractually due, we classify landlord incentives as deferred rent on the Consolidated Balance Sheets and amortize the landlord incentives on a straight-line basis over the lease term as a reduction of occupancy costs and related expenses or pre-opening costs on the Consolidated Statements of Income (Loss) . Lease Financing Arrangements In certain leasing arrangements, due to our involvement in the construction of the leased assets, we are considered the owner of the leased assets for accounting purposes. In such cases, in addition to capitalizing our own construction costs, we capitalize the construction costs funded by the landlord related to our leased premises, and also recognize a corresponding liability for those costs as deemed landlord financing. If, upon completion of construction, the arrangement does not meet the sales recognition criteria under the sale-leaseback accounting guidance, we are precluded from de-recognizing the landlord-funded asset and related financing obligation and continue to account for the landlord-funded asset as if we were the legal owner. If de-recognition is permitted we are required to account for the lease as either an operating or capital lease. As of December 26, 2018 , we were deemed to be the accounting owner of 24 leased Shacks, one of which was under construction as of the end of the period. As of December 27, 2017 , we were deemed to be the accounting owner of 23 leased Shacks, 11 of which were under construction as of the end of the period.
Revenue Recognition	Revenue Recognition
Income Taxes	Income Taxes We account for income taxes pursuant to the asset and liability method which requires the recognition of deferred income tax assets and liabilities related to the expected future tax consequences arising from temporary differences between the carrying amounts and tax bases of assets and liabilities based on enacted statutory tax rates applicable to the periods in which the temporary differences are expected to reverse. Any effects of changes in income tax rates or laws are included in income tax expense in the period of enactment. A valuation allowance is recognized if we determine it is more likely than not that all or a portion of a deferred tax asset will not be recognized.
Pre-Opening Costs	Pre-Opening Costs Pre-opening costs are expensed as incurred and consist primarily of legal fees, marketing expenses, occupancy, manager and employee wages, travel and related training costs incurred prior to the opening of a Shack.
Advertising	Advertising The cost of advertising is expensed as incurred.
Recently Issued Accounting Pronouncements	Recently Adopted Accounting Pronouncements We adopted the Accounting Standards Updates (“ASUs”) summarized below in fiscal 2018. Accounting Standards Update (“ASU”) Description Date Adopted Revenue from Contracts with Customers and related standards (ASU’s 2014-09, 2015-14, 2016-08, 2016-10, 2016-12, 2016-20) This standard supersedes the existing revenue recognition guidance and provides a new framework for recognizing revenue. The core principle of the standard is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods and services. The new standard also requires significantly more comprehensive disclosures than the existing standard. Guidance subsequent to ASU 2014-09 has been issued to clarify various provisions in the standard, including principal versus agent considerations, identifying performance obligations, licensing transactions, as well as various technical corrections and improvements. See Note 3 for more information. December 28, 2017 Recognition and Measurement of Financial Assets and Financial Liabilities (ASU 2016-01) For public business entities, this standard requires: (i) certain equity investments to be measured at fair value with changes in fair value recognized in net income; (ii) a qualitative assessment to identify impairment of equity investments without readily determinable fair values; (iii) elimination of the requirement to disclose the method(s) and significant assumptions used to estimate the fair value for financial instruments measured at amortized cost on the balance sheet; (iv) use of the exit price notion when measuring the fair value of financial instruments for disclosure purposes; (v) separate presentation in other comprehensive income of the portion of the total change in the fair value of a liability resulting from a change in the instrument-specific credit risk when the entity has elected to measure the liability at fair value in accordance with the fair value option for financial instruments; (vi) separate presentation of financial assets and liabilities by measurement category and form of financial asset in the financial statements; and (vii) an entity to evaluate the need for a valuation allowance on a deferred tax asset related to available-for-sale securities in combination with the entity’s other deferred tax assets. The adoption of this standard did not have a material impact to our consolidated financial statements. December 28, 2017 Statement of Cash Flows: Classification of Certain Cash Receipts and Payments (ASU 2016-15) This standard provides guidance on eight specific cash flow issues with the objective of reducing diversity in practice. The adoption of this standard did not have a material impact to our consolidated financial statements. December 28, 2017 Customer's Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract (ASU 2018-15) This standard provides additional guidance on accounting for costs of implementation activities performed in a cloud computing arrangement that is a service contract. The standard aligns the requirements for capitalizing implementation costs of such arrangements with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software. The standard also clarifies the presentation and classification of the capitalized costs, amortization expense, and the associated treatment in the statement of cash flows by aligning these items with the same treatment for costs of the hosting service itself. We adopted this standard on a prospective basis on September 27, 2018, and began capitalizing certain costs related to the implementation of an enterprise-wide system initiative that previously would have been expensed. As of December 26, 2018, we have capitalized certain implementation costs within other assets. We will begin amortizing the implementation costs once the system is ready for its intended use, on a straight-line basis, over the term of the related service agreements. The amortization expense related to cloud computing arrangements that are service contracts will be recorded within general and administrative expenses. September 27, 2018 Recently Issued Accounting Pronouncements Accounting Standards Update (“ASU”) Description Expected Impact Effective Date Leases (ASU's 2016-02, 2018-01, 2018-10, 2018-11) This standard establishes a new lease accounting model, which introduces the recognition of lease assets and liabilities for those leases classified as operating leases under previous GAAP. It should be applied using a modified retrospective approach applied either at the beginning of the earliest period presented, or at the adoption date, with the option to elect various practical expedients. Early adoption is permitted. We will adopt the standard on December 27, 2018, electing the optional transition method to apply the standard as of the transition date. As a result, we will not apply the standard to the comparative periods presented. We have elected the transition package of three practical expedients permitted under the new standard, which among other things, allows us to carryforward our historical lease classifications. We also made certain accounting policy elections for new leases post-transition, including the election to combine components. The adoption will have a significant impact to our consolidated balance sheet given the extent of our real estate lease portfolio. We will derecognize all landlord funded assets, deemed financing liabilities and deferred rent liabilities upon transition. We will record a right-of-use asset and lease liability for those leases as well as all other existing leases, the majority of which are real estate operating leases. We expect the adoption to result in a net increase of between $207,000 to $217,000 in lease assets and $202,000 to $212,000 in lease liabilities. The difference between the additional lease assets and lease liabilities, net of tax, will be recorded as an adjustment through equity. Our existing operating leases will not have a material impact on our statement of income post-transition. For those leases where we are involved in construction and deemed to be the accounting owner, they will be accounted for as operating leases post-transition, resulting in an increase to occupancy and related expenses, and a decrease to interest and depreciation expense. We are substantially complete with our implementation efforts. December 27, 2018

REVENUE (Tables)

REVENUE (Tables)	12 Months Ended
	Dec. 26, 2018
Revenue from Contract with Customer [Abstract]
Schedule of New Accounting Pronouncements and Changes in Accounting Principles	Revenue recognized during fiscal 2018 under ASC 606 and revenue that would have been recognized during fiscal 2018 had ASC 605 been applied is as follows: As reported under ASC 606 If reported under ASC 605 Increase (decrease) Shack sales $ 445,589 $ 445,589 $ — Licensing revenue 13,721 14,389 (668 ) Total revenue $ 459,310 $ 459,978 $ (668 ) Revenue recognized during fiscal 2018 (under ASC 606) and fiscal 2017 and 2016 (under ASC 605) disaggregated by type is as follows: December 26 December 27 December 28 Shack sales $ 445,589 $ 346,388 $ 259,350 Licensing revenue: Sales-based royalties 13,422 11,633 8,765 Initial territory and opening fees 299 789 360 Total revenue $ 459,310 $ 358,810 $ 268,475
Contract with Customer, Asset and Liability	Opening and closing balances of contract liabilities and receivables from contracts with customers for fiscal 2018 is as follows: December 26 December 28 Shack sales receivables $ 2,550 $ 2,184 Licensing receivables 2,616 1,522 Gift card liability 1,796 1,472 Deferred revenue, current 307 265 Deferred revenue, long-term 10,026 3,742

FAIR VALUE MEASUREMENTS (Tables

FAIR VALUE MEASUREMENTS (Tables)	12 Months Ended
	Dec. 26, 2018
Fair Value Disclosures [Abstract]
Schedule of Cash and Cash Equivalents	The following tables summarize our cash, cash equivalents and marketable securities by significant investment categories as of December 26, 2018 and December 27, 2017 : December 26, 2018 Cost Basis Gross Unrealized Gains Gross Unrealized Losses Fair Value Cash and Cash Equivalents Marketable Securities Cash $ 19,746 $ — $ — $ 19,746 $ 19,746 $ — Level 1: Money market funds 5,004 — — 5,004 5,004 — Mutual funds 62,235 — (122 ) 62,113 — 62,113 Level 2: Corporate debt securities (1) — — — — — — Total $ 86,985 $ — $ (122 ) $ 86,863 $ 24,750 $ 62,113 December 27, 2017 Cost Basis Gross Unrealized Gains Gross Unrealized Losses Fair Value Cash and Cash Equivalents Marketable Securities Cash $ 16,138 $ — $ — $ 16,138 $ 16,138 $ — Level 1: Money market funds 5,369 — — 5,369 5,369 — Mutual funds 60,985 — (61 ) 60,924 — 60,924 Level 2: Corporate debt securities (1) 2,125 2 (15 ) 2,112 — 2,112 Total $ 84,617 $ 2 $ (76 ) $ 84,543 $ 21,507 $ 63,036 (1) Corporate debt securities were measured at fair value using a market approach utilizing observable prices for identical securities or securities with similar characteristics and inputs that are observable or can be corroborated by observable market data.
Schedule of Unrealized Loss on Investments	The following tables summarize the gross unrealized losses and fair values for investments in debt securities that were in an unrealized loss position as of December 26, 2018 and December 27, 2017 , aggregated by length of time that individual securities have been in a continuous loss position: Less than 12 Months 12 Months or Greater Total Fair Value Unrealized Loss Fair Value Unrealized Loss Fair Value Unrealized Loss As of December 26, 2018 — — — — — — As of December 27, 2017 1,675 (12 ) 162 (3 ) 1,837 (15 )
Schedule of Gain (Loss) on Investments	A summary of other income from available-for-sale securities recognized during fiscal 2018 , 2017 and 2016 is as follows: 2018 2017 2016 Available-for-sale securities: Dividend income $ 1,392 $ 830 $ 296 Interest income 9 77 88 Loss on investments (3 ) (5 ) (7 ) Unrealized loss on available-for-sale equity securities (61 ) — — Total other income, net $ 1,337 $ 902 $ 377
Schedule of Realized Gain (Loss)	A summary of available-for-sale securities sold and gross realized gains and losses recognized during fiscal 2018 , 2017 and 2016 is as follows: 2018 2017 2016 Available-for-sale securities: Gross proceeds from sales and redemptions $ 2,144 $ 2,223 $ 938 Cost basis of sales and redemptions 2,160 2,271 956 Gross realized gains included in net income 2 1 2 Gross realized losses included in net income (18 ) (49 ) (20 ) Amounts reclassified out of accumulated other comprehensive loss 16 47 19

ACCOUNTS RECEIVABLE (Tables)

ACCOUNTS RECEIVABLE (Tables)	12 Months Ended
	Dec. 26, 2018
Receivables [Abstract]
Schedule of Accounts Receivable	The components of accounts receivable as of December 26, 2018 and December 27, 2017 are as follows: December 26 December 27 Landlord receivables $ 4,494 $ 1,660 Licensing receivables 2,579 1,422 Credit card receivables 2,446 2,018 Other receivables 1,004 541 Accounts receivable $ 10,523 $ 5,641

INVENTORIES (Tables)

INVENTORIES (Tables)	12 Months Ended
	Dec. 26, 2018
Inventory Disclosure [Abstract]
Inventories	Inventories consisted of the following: December 26 December 27 Food $ 1,291 $ 874 Wine 83 69 Beer 95 85 Beverages 203 111 Retail merchandise 77 119 Inventories $ 1,749 $ 1,258

PROPERTY AND EQUIPMENT (Tables)

PROPERTY AND EQUIPMENT (Tables)	12 Months Ended
	Dec. 26, 2018
Property, Plant and Equipment [Abstract]
Schedule of Property and Equipment	Property and equipment consisted of the following: December 26 December 27 Leasehold improvements $ 228,453 $ 166,963 Landlord funded assets 15,595 7,472 Equipment 40,716 31,608 Furniture and fixtures 14,055 10,128 Computer equipment and software 19,008 12,721 Construction in progress (includes assets under construction from deemed landlord financing) 29,474 16,458 Property and equipment, gross 347,301 245,350 Less: accumulated depreciation (85,447 ) (58,255 ) Property and equipment, net $ 261,854 $ 187,095

SUPPLEMENTAL BALANCE SHEET IN_2

SUPPLEMENTAL BALANCE SHEET INFORMATION (Tables)	12 Months Ended
	Dec. 26, 2018
Supplemental Balance Sheet Disclosures [Abstract]
Components of Other Current Liabilities	The components of other current liabilities as of December 26, 2018 and December 27, 2017 are as follows: December 26 December 27 Sales tax payable $ 3,143 $ 1,813 Current portion of liabilities under tax receivable agreement 5,804 937 Gift card liability 1,796 1,472 Other 3,287 3,715 Other current liabilities $ 14,030 $ 7,937

LEASES (Tables)

LEASES (Tables)	12 Months Ended
	Dec. 26, 2018
Leases [Abstract]
Schedule of Rent Expense	A summary of rent expense under operating lease agreements is as follows: 2018 2017 2016 Minimum rent $ 24,920 $ 20,421 $ 15,408 Deferred rent 1,241 838 2,122 Contingent rent 4,805 4,902 4,294 Total rent expense $ 30,966 $ 26,161 $ 21,824
Schedule of Future Minimum Rental Payments	As of December 26, 2018 , future minimum lease payments under non-cancelable operating leases and lease financing arrangements consisted of the following: Operating Leases Deemed Landlord Financing (1) 2019 $ 31,785 $ 4,487 2020 32,819 4,755 2021 33,363 4,816 2022 33,934 4,889 2023 33,588 5,085 Thereafter 174,145 22,659 Total minimum lease payments $ 339,634 $ 46,691 (1) Amounts include minimum lease payments for one lease under construction as of December 26, 2018 where we are deemed the accounting owner. Final classification of lease payments under deemed landlord financing is subject to change pending sale lease-back analysis performed at the store opening date.

NON-CONTROLLING INTERESTS (Tabl

NON-CONTROLLING INTERESTS (Tables)	12 Months Ended
	Dec. 26, 2018
Noncontrolling Interest [Abstract]
Schedule of Ownership Interest in SSE Holdings	The following table summarizes the ownership interest in SSE Holdings as of December 26, 2018 and December 27, 2017 : 2018 2017 LLC Interests Ownership % LLC Interests Ownership % Number of LLC Interests held by Shake Shack Inc. 29,520,833 79.6 % 26,527,477 72.1 % Number of LLC Interests held by non-controlling interest holders 7,557,347 20.4 % 10,250,007 27.9 % Total LLC Interests outstanding 37,078,180 100.0 % 36,777,484 100.0 %
Schedule of Non-Controlling Interest	The following table summarizes the effects of changes in ownership in SSE Holdings on our equity during fiscal 2018 , 2017 and 2016 . 2018 2017 2016 Net income (loss) attributable to Shake Shack Inc. $ 15,179 $ (320 ) $ 12,446 Other comprehensive income (loss): Unrealized holding gains (losses) on available-for-sale securities 10 (34 ) (10 ) Transfers (to) from non-controlling interests: Increase in additional paid-in capital as a result of the redemption of LLC Interests 15,202 4,415 16,986 Increase in additional paid-in capital as a result of activity under the stock compensation plan and the related income tax effect 2,509 4,451 825 Total effect of changes in ownership interest on equity attributable to Shake Shack Inc. $ 32,900 $ 8,512 $ 30,247

EQUITY-BASED COMPENSATION (Tabl

EQUITY-BASED COMPENSATION (Tables)	12 Months Ended
	Dec. 26, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of Equity-Based Compensation Expense Recognized	A summary of equity-based compensation expense recognized during fiscal 2018 , 2017 and 2016 is as follows: 2018 2017 2016 Stock options 3,039 3,474 4,262 Performance stock units 2,449 1,869 1,092 Restricted stock units 655 280 — Equity-based compensation expense $ 6,143 $ 5,623 $ 5,354 Total income tax benefit recognized related to equity-based compensation $ 172 $ 198 $ 168 Equity-based compensation expense is allocated to general and administrative expenses and labor and related expenses on the Consolidated Statements of Income (Loss) during fiscal 2018 , 2017 and 2016 as follows: 2018 2017 2016 General and administrative expenses 5,991 5,463 5,260 Labor and related expenses 152 160 94 Equity-based compensation expense 6,143 5,623 5,354
Schedule of Fair Value of Stock Options	The fair value of stock option awards was determined on the grant date using the Black-Scholes valuation model based on the following weighted-average assumptions: 2018 2017 2016 Expected term (years) (1) 7.5 7.5 5.5 Expected volatility (2) 42.5 % 44.5 % 50.7 % Risk-free interest rate (3) 2.8 % 2.1 % 1.5 % Dividend yield (4) — % — % — % (1) Expected term represents the estimated period of time until an award is exercised and was determined using the simplified method. (2) Expected volatility is based on the historical volatility of a selected peer group over a period equivalent to the expected term. (3) The risk-free rate rate is an interpolation of yields on U.S. Treasury securities with maturities equivalent to the expected term. (4) We have assumed a dividend yield of zero as we have no plans to declare dividends in the foreseeable future.
Schedule of Stock Options, Activity	A summary of stock option activity for fiscal years 2018 , 2017 and 2016 is as follows: Stock Options Weighted Average Exercise Price Aggregate Intrinsic Value Weighted Average Remaining Contractual Life (Years) Outstanding as of December 30, 2015 2,574,981 $ 21.00 Granted 16,931 34.74 Exercised (160,230 ) 21.00 Forfeited (66,960 ) (21.00 ) Expired — — Outstanding as of December 28, 2016 2,364,722 $ 21.10 Granted 5,150 38.91 Exercised (359,011 ) 21.13 Forfeited (291,520 ) (21.00 ) Expired — — Outstanding as of December 27, 2017 1,719,341 $ 21.16 Granted 5,036 39.91 Exercised (260,515 ) 21.00 Forfeited (102,879 ) (21.27 ) Expired — — Outstanding as of December 26, 2018 1,360,983 $ 21.25 $ 29,881 6.1 Options vested and exercisable as of December 26, 2018 674,247 $ 21.26 $ 14,798 6.1 Options expected to vest as of December 26, 2018 686,736 $ 21.25 $ 15,083 6.1
Schedule of Nonvested Share Activity	As of December 26, 2018 , total unrecognized compensation expense related to unvested stock options was $3,335
Schedule of Information About Stock Options	The following table summarizes information about stock options outstanding and exercisable as December 26, 2018 : Options Outstanding Options Exercisable Number Outstanding at December 26, 2018 Weighted Average Remaining Contractual Life (Years) Weighted Average Exercise Price Number Exercisable at December 26, 2018 Weighted Average Remaining Contractual Life (Years) Weighted Average Exercise Price Exercise Price $21.00 1,339,274 6.1 $ 21.00 661,694 6.1 $ 21.00 $34.62 10,415 7.4 $ 34.62 10,415 7.4 $ 34.62 $36.41 1,108 7.9 $ 36.41 1,108 7.9 $ 36.41 $38.91 5,150 8.5 $ 38.91 1,030 8.5 $ 38.91 $39.91 5,036 9.2 $ 39.91 — — $ —
Schedule of Stock Options Outstanding and Exercisable, Option Plans	A summary of performance stock unit activity for fiscal years 2018 , 2017 and 2016 is as follows: Performance Stock Units Weighted Average Grant Date Fair Value Outstanding as of December 30, 2015 — $ — Granted 63,600 38.41 Performance achievement (1) — — Vested — — Forfeited (2,000 ) 38.43 Expired — — Outstanding as of December 28, 2016 61,600 $ 38.41 Granted 87,596 37.90 Performance achievement (1) 9,545 38.40 Vested (22,703 ) 38.40 Forfeited (11,196 ) 38.28 Expired — — Outstanding as of December 27, 2017 124,842 $ 38.06 Granted 60,437 58.46 Performance achievement (1) (12,139 ) 37.89 Vested (43,861 ) 38.13 Forfeited (10,737 ) 41.28 Expired — — Outstanding as of December 26, 2018 118,542 $ 48.16 (1) Represents the incremental awards earned and/or awards forfeited based on the achievement of performance conditions

INCOME TAXES (Tables)

INCOME TAXES (Tables)	12 Months Ended
	Dec. 26, 2018
Income Tax Disclosure [Abstract]
Schedule of Income before Income Tax, Domestic and Foreign	The components of income before income taxes are follows: 2018 2017 2016 Domestic $ 21,595 $ 152,204 $ 20,623 Foreign 9,215 8,089 7,873 Income before income taxes $ 30,810 $ 160,293 $ 28,496
Schedule of Components of Income Tax Expense	The components of income tax expense are as follows: 2018 2017 2016 Current income taxes: Federal $ 5,281 $ 518 $ 3,767 State and local 858 3,615 2,439 Foreign 1,935 942 667 Total current income taxes 8,074 5,075 6,873 Deferred income taxes: Federal (210 ) 145,139 (48 ) State and local 998 1,195 (475 ) Total deferred income taxes 788 146,334 (523 ) Income tax expense $ 8,862 $ 151,409 $ 6,350
Reconciliation of Income Tax Expense, US Income Tax Rate	Reconciliations of income tax expense computed at the U.S. federal statutory income tax rate to the recognized income tax expense and the U.S. statutory income tax rate to our effective tax rates are as follows: 2018 2017 2016 Expected U.S. federal income taxes at statutory rate $ 6,470 21.0 % $ 56,103 35.0 % $ 9,689 34.0 % State and local income taxes, net of federal benefit 797 2.6 % 2,590 1.6 % 1,461 5.1 % Foreign withholding taxes 1,935 6.3 % 942 0.6 % 667 2.3 % Tax credits (2,151 ) (7.0 )% (1,230 ) (0.8 )% (779 ) (2.7 )% Non-controlling interest (1,908 ) (6.2 )% (3,273 ) (2.0 )% (3,765 ) (13.2 )% Remeasurement of deferred tax assets in connection with the enactment of the TCJA — — % 138,636 86.5 % — — % Remeasurement of deferred tax assets in connection with other tax rate changes 3,794 12.3 % 1,657 1.0 % (1,353 ) (4.7 )% Remeasurement of liabilities under tax receivable agreement in connection with the enactment of the TCJA — — % (44,051 ) (27.4 )% — — % Other (75 ) (0.2 )% 35 — % 430 1.5 % Income tax expense $ 8,862 28.8 % $ 151,409 94.5 % $ 6,350 22.3 %
Schedule of Deferred Tax Assets and Liabilities	The components of deferred tax assets and liabilities are as follows: December 26 December 27 Deferred tax assets: Investment in partnership $ 168,451 $ 137,449 Tax Receivable Agreement 57,203 43,464 Deferred rent 1,109 571 Deferred revenue 184 59 Stock-based compensation 375 322 Net operating loss carryforwards 18,046 12,332 Tax credits 5,194 2,328 Other assets 331 176 Total gross deferred tax assets 250,893 196,701 Valuation allowance (6,925 ) (10,114 ) Total deferred tax assets, net of valuation allowance 243,968 186,587 Deferred tax liabilities: Property and equipment (1,435 ) (673 ) Total gross deferred tax liabilities (1,435 ) (673 ) Net deferred tax assets $ 242,533 $ 185,914

EARNINGS PER SHARE (Tables)

EARNINGS PER SHARE (Tables)	12 Months Ended
	Dec. 26, 2018
Earnings Per Share [Abstract]
Schedule of Earnings Per Share	The following table sets forth reconciliations of the numerators and denominators used to compute basic and diluted earnings per share of Class A common stock for fiscal 2018 , 2017 and 2016 . 2018 2017 2016 Numerator: Net income $ 21,948 $ 8,884 $ 22,146 Less: net income attributable to non-controlling interests 6,769 9,204 9,700 Net income (loss) attributable to Shake Shack Inc. $ 15,179 $ (320 ) $ 12,446 Denominator: Weighted-average shares of Class A common stock outstanding—basic 28,299 25,876 22,956 Effect of dilutive securities: Stock options 798 — 491 Performance stock units 63 — 2 Restricted stock units 19 — — Weighted-average shares of Class A common stock outstanding—diluted 29,179 25,876 23,449 Earnings (loss) per share of Class A common stock—basic $ 0.54 $ (0.01 ) $ 0.54 Earnings (loss) per share of Class A common stock—diluted $ 0.52 $ (0.01 ) $ 0.53
Schedule of Antidilutive Securities	The following table presents potentially dilutive securities excluded from the computations of diluted earnings per share of Class A common stock for fiscal 2018 , 2017 and 2016 . 2018 2017 2016 Stock options — 1,719,341 (2) 125 (1) Performance stock units 21,560 (3) 124,842 (2) 26,860 (3) Restricted stock units — 44,476 (2) — Shares of Class B common stock 7,557,347 (4) 10,250,007 (4) 11,253,592 (4) (1) Weighted-average number of securities excluded from the computation of diluted earnings per share of Class A common stock because the exercise price of the stock options exceeded the average market price of our Class A common stock during the period ("out-of-the-money"). (2) Represents number of instruments outstanding at the end of the period that were excluded from the computation of diluted earnings per share of Class A common stock because the effect would have been anti-dilutive. (3) Weighted-average number of securities excluded from the computation of diluted earnings per share of Class A common stock because the performance conditions were not met for a portion of the fiscal year. (4) Shares of our Class B common stock are considered potentially dilutive shares of Class A common stock. Amounts have been excluded from the computations of diluted earnings per share of Class A common stock because the effect would have been anti-dilutive under the if-converted and two-class methods.

SUPPLEMENTAL CASH FLOW INFORM_2

SUPPLEMENTAL CASH FLOW INFORMATION (Tables)	12 Months Ended
	Dec. 26, 2018
Supplemental Cash Flow Elements [Abstract]
Schedule of Cash Flow Information	The following table sets forth supplemental cash flow information for fiscal 2018 , 2017 and 2016 : 2018 2017 2016 Cash paid for: Income taxes, net of refunds $ 3,272 $ 2,261 $ 1,823 Interest, net of amounts capitalized 2,261 1,106 54 Non-cash investing activities: Accrued purchases of property and equipment 17,443 7,526 6,150 Capitalized landlord assets for leases where we are deemed the accounting owner 5,443 10,125 1,985 Capitalized equity-based compensation 107 109 139 Non-cash financing activities: Class A common stock issued in connection with the redemption of LLC Interests 2 1 5 Cancellation of Class B common stock in connection with the redemption of LLC Interests (2 ) (1 ) (5 ) Establishment of liabilities under tax receivable agreement 44,338 18,973 100,063 Accrued distributions payable to non-controlling interest holders — — 607

GEOGRAPHIC INFORMATION (Tables)

GEOGRAPHIC INFORMATION (Tables)	12 Months Ended
	Dec. 26, 2018
Segment Reporting [Abstract]
Revenue from Customers by Geographic Areas	Revenue by geographic area for fiscal 2018 , 2017 and 2016 is as follows: 2018 2017 2016 United States $ 447,575 $ 348,575 $ 260,602 Other countries 11,735 10,235 7,873 Total revenue $ 459,310 $ 358,810 $ 268,475

SELECTED QUARTERLY FINANCIAL _2

SELECTED QUARTERLY FINANCIAL DATA (UNAUDITED) (Tables)	12 Months Ended
	Dec. 26, 2018
Quarterly Financial Information Disclosure [Abstract]
Schedule of Quarterly Financial Information	The following table sets forth certain unaudited financial information for each quarter of fiscal 2018 and 2017 . The unaudited quarterly information includes all adjustments (consisting of normal recurring adjustments) that, in the opinion of management, are necessary for the fair presentation of the information presented. Operating results for interim periods are not necessarily indicative of the results that may be expected for a full fiscal year. 2018 First Second Third Fourth Quarter Quarter Quarter Quarter Total revenue $ 99,116 $ 116,282 $ 119,647 $ 124,265 Operating income 6,514 13,018 9,343 2,836 Net income (loss) 4,979 10,571 6,946 (548 ) Net income (loss) attributable to Shake Shack Inc. 3,508 7,604 5,025 (958 ) Earnings (loss) per share (1) : Basic $ 0.13 $ 0.27 $ 0.17 $ (0.03 ) Diluted $ 0.13 $ 0.26 $ 0.17 $ (0.03 ) 2017 First Second Third Fourth Quarter Quarter Quarter Quarter Total revenue $ 76,749 $ 91,316 $ 94,609 $ 96,136 Operating income 5,628 11,737 10,610 5,838 Net income (loss) 3,682 8,184 7,870 (11,032 ) Net income (loss) attributable to Shake Shack Inc. 2,267 4,879 4,997 (12,463 ) Earnings (loss) per share (1) : Basic $ 0.09 $ 0.19 $ 0.19 $ (0.47 ) Diluted $ 0.09 $ 0.19 $ 0.19 $ (0.47 ) (1) Basic and diluted earnings per share are computed independently for each of the quarters presented. Therefore, the sum of quarterly basic and diluted earnings per share amounts may not equal annual basic and diluted earnings per share amounts.

NATURE OF OPERATIONS - Organiza

NATURE OF OPERATIONS - Organization and Nature of Operations - Franchiser (Details)	Dec. 26, 2018Restaurant
Franchisor Disclosure [Line Items]
Number of Restaurants	208
Company-operated | United States
Franchisor Disclosure [Line Items]
Number of Restaurants	124
Licensed | United States
Franchisor Disclosure [Line Items]
Number of Restaurants	12
Licensed | Other countries
Franchisor Disclosure [Line Items]
Number of Restaurants	72

NATURE OF OPERATIONS - Organi_2

NATURE OF OPERATIONS - Organizational Transactions (Details)	Feb. 04, 2015	Dec. 26, 2018shares	Dec. 27, 2017shares
Class of Stock [Line Items]
LLC interests acquired (in shares)		2,692,660	1,003,585
Ownership percent of noncontrolling interest		79.60%	72.10%
Noncontrolling owners ownership percentage		20.40%	27.90%
Class B Common Stock | Common stock
Class of Stock [Line Items]
Effect of redemption (in shares)		2,692,660	1,003,585
Class A Common Stock
Class of Stock [Line Items]
Ratio of common stock to limited liability company interest	1

NATURE OF OPERATIONS - Secondar

NATURE OF OPERATIONS - Secondary Offering (Details) - shares	12 Months Ended
	Dec. 26, 2018	Dec. 27, 2017
Class of Stock [Line Items]
Units acquired during the period (in shares)	2,692,660	1,003,585
Ownership percent of noncontrolling interest	79.60%	72.10%
Noncontrolling owners ownership percentage	20.40%	27.90%
Class A Common Stock | Common stock
Class of Stock [Line Items]
Redemptions (in shares)	2,692,660	1,003,585
Class B Common Stock | Common stock
Class of Stock [Line Items]
Effect of redemption (in shares)	2,692,660	1,003,585
Limited Liability Company
Class of Stock [Line Items]
Number of units redeemed (in shares)	2,692,660	1,003,585
Units acquired during the period (in shares)	2,993,356

SUMMARY OF SIGNIFICANT ACCOUN_3

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Basis of Presentation (Details) - USD ($) $ in Thousands	Dec. 26, 2018	Dec. 27, 2017
Variable Interest Entity, Primary Beneficiary
Variable Interest Entity [Line Items]
Net assets of SSE Holdings	$ 232,711	$ 197,301

SUMMARY OF SIGNIFICANT ACCOUN_4

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Segment Reporting (Details)	12 Months Ended
	Dec. 26, 2018reportable_segmentoperating_segment
Accounting Policies [Abstract]
Number of operating segments | operating_segment	1
Number of reportable segments | reportable_segment	1

SUMMARY OF SIGNIFICANT ACCOUN_5

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Property and Equipment (Details) - USD ($)	12 Months Ended
	Dec. 26, 2018	Dec. 27, 2017	Dec. 28, 2016
Property, Plant and Equipment [Line Items]
Impairment charges	$ 0	$ 0	$ 0
Equipment | Minimum
Property, Plant and Equipment [Line Items]
Useful life of asset	3 years
Equipment | Maximum
Property, Plant and Equipment [Line Items]
Useful life of asset	7 years
Furniture and fixtures | Minimum
Property, Plant and Equipment [Line Items]
Useful life of asset	3 years
Furniture and fixtures | Maximum
Property, Plant and Equipment [Line Items]
Useful life of asset	7 years
Computer equipment and software | Minimum
Property, Plant and Equipment [Line Items]
Useful life of asset	3 years
Computer equipment and software | Maximum
Property, Plant and Equipment [Line Items]
Useful life of asset	7 years
Leasehold improvements | Minimum
Property, Plant and Equipment [Line Items]
Useful life of asset	10 years
Leasehold improvements | Maximum
Property, Plant and Equipment [Line Items]
Useful life of asset	15 years
Landlord funded assets | Minimum
Property, Plant and Equipment [Line Items]
Useful life of asset	10 years
Landlord funded assets | Maximum
Property, Plant and Equipment [Line Items]
Useful life of asset	15 years

SUMMARY OF SIGNIFICANT ACCOUN_6

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Other Assets (Details) - USD ($) $ in Thousands	Dec. 26, 2018	Dec. 27, 2017
Accounting Policies [Abstract]
Indefinite-lived intangible assets	$ 1,159	$ 894

SUMMARY OF SIGNIFICANT ACCOUN_7

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Leases (Details)	12 Months Ended
	Dec. 26, 2018renewal_optionlease	Dec. 27, 2017lease
Operating Leased Assets [Line Items]
Number of renewal options | renewal_option	2
Period of renewal term	5 years
Number of sale leaseback transactions, accounting owner	24	23
Number of sale leaseback transactions	1	11
Minimum
Operating Leased Assets [Line Items]
Terms of lease contract	10 years
Maximum
Operating Leased Assets [Line Items]
Terms of lease contract	15 years

SUMMARY OF SIGNIFICANT ACCOUN_8

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Advertising (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 26, 2018	Dec. 27, 2017	Dec. 28, 2016
Accounting Policies [Abstract]
Advertising and promotions	$ 399	$ 357	$ 147

SUMMARY OF SIGNIFICANT ACCOUN_9

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - ASU Update (Details) - USD ($) $ in Thousands	Mar. 28, 2018	Dec. 28, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New accounting pronouncement	$ (1,574)
Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New accounting pronouncement	$ (1,174)	$ 1,574
Other Noncurrent Liabilities
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New accounting pronouncement		1,769
Current Liabilities
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New accounting pronouncement		68
Accounts Receivable
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New accounting pronouncement		$ 100

REVENUE Narrative (Details)

REVENUE Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 26, 2018	Dec. 27, 2017	Dec. 28, 2017
Disaggregation of Revenue [Line Items]
Other long-term liabilities	$ 10,498	$ 2,553
Other current liabilities	(14,030)	(7,937)
Remaining performance obligation	15,333
Increase in gift card liability	506
Deferred revenue current	$ 253
ASC 2014-09
Disaggregation of Revenue [Line Items]
Decrease in equity		(1,574)
Other long-term liabilities			$ 1,769
Other current liabilities			(68)
Accounts receivable			$ 100
ASC 2014-09 | Retained Earnings
Disaggregation of Revenue [Line Items]
Decrease in equity		(1,135)
ASC 2014-09 | Non- Controlling Interest
Disaggregation of Revenue [Line Items]
Decrease in equity		$ (439)

REVENUE Schedule of Revenue Rec

REVENUE Schedule of Revenue Recognized (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 26, 2018	Sep. 26, 2018	Jun. 27, 2018	Mar. 28, 2018	Dec. 27, 2017	Sep. 27, 2017	Jun. 28, 2017	Mar. 29, 2017	Dec. 26, 2018	Dec. 27, 2017	Dec. 28, 2016
Disaggregation of Revenue [Line Items]
TOTAL REVENUE	$ 124,265	$ 119,647	$ 116,282	$ 99,116	$ 96,136	$ 94,609	$ 91,316	$ 76,749	$ 459,310	$ 358,810	$ 268,475
Shack sales
Disaggregation of Revenue [Line Items]
TOTAL REVENUE									445,589	346,388	259,350
Licensing revenue
Disaggregation of Revenue [Line Items]
TOTAL REVENUE									13,721	$ 12,422	$ 9,125
If reported under ASC 605
Disaggregation of Revenue [Line Items]
TOTAL REVENUE									459,978
If reported under ASC 605 | Shack sales
Disaggregation of Revenue [Line Items]
TOTAL REVENUE									445,589
If reported under ASC 605 | Licensing revenue
Disaggregation of Revenue [Line Items]
TOTAL REVENUE									14,389
ASC 2014-09 | Increase (decrease)
Disaggregation of Revenue [Line Items]
TOTAL REVENUE									(668)
ASC 2014-09 | Increase (decrease) | Shack sales
Disaggregation of Revenue [Line Items]
TOTAL REVENUE									0
ASC 2014-09 | Increase (decrease) | Licensing revenue
Disaggregation of Revenue [Line Items]
TOTAL REVENUE									$ (668)

REVENUE Disaggregation of Reven

REVENUE Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 26, 2018	Sep. 26, 2018	Jun. 27, 2018	Mar. 28, 2018	Dec. 27, 2017	Sep. 27, 2017	Jun. 28, 2017	Mar. 29, 2017	Dec. 26, 2018	Dec. 27, 2017	Dec. 28, 2016
Disaggregation of Revenue [Line Items]
TOTAL REVENUE	$ 124,265	$ 119,647	$ 116,282	$ 99,116	$ 96,136	$ 94,609	$ 91,316	$ 76,749	$ 459,310	$ 358,810	$ 268,475
Shack sales
Disaggregation of Revenue [Line Items]
TOTAL REVENUE									445,589	346,388	259,350
Sales-based royalties
Disaggregation of Revenue [Line Items]
TOTAL REVENUE									13,422	11,633	8,765
Initial territory and opening fees
Disaggregation of Revenue [Line Items]
TOTAL REVENUE									$ 299	$ 789	$ 360

REVENUE Contract Balances (Deta

REVENUE Contract Balances (Details) - USD ($) $ in Thousands	Dec. 26, 2018	Dec. 27, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Gift card liability	$ 1,796	$ 1,472
Deferred revenue, current	307	265
Deferred revenue, long-term	10,026	3,742
Shack sales
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Contract with customer, asset, net	2,550	2,184
Licensing receivables
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Contract with customer, asset, net	$ 2,616	$ 1,522

FAIR VALUE MEASUREMENTS - Cash,

FAIR VALUE MEASUREMENTS - Cash, Cash Equivalents and Marketable Securities (Details) - USD ($) $ in Thousands	Dec. 26, 2018	Dec. 27, 2017	Dec. 28, 2016	Dec. 30, 2015
Debt Securities, Available-for-sale [Line Items]
Cost Basis	$ 24,750	$ 21,507	$ 11,607	$ 70,849
Cash and cash equivalents fair value	24,750	21,507
Gross Unrealized Gains	0	2
Gross Unrealized Losses	(122)	(76)
Fair value of marketable securities	62,113	63,036
Total cost basis	86,985	84,617
Total fair value	86,863	84,543
Level 1: | Mutual Fund
Debt Securities, Available-for-sale [Line Items]
Cost Basis	62,235	60,985
Cash and cash equivalents fair value	62,113	60,924
Gross Unrealized Gains	0
Gross Unrealized Losses	(122)	(61)
Fair value of marketable securities	62,113	60,924
Level 2: | Corporate debt securities
Debt Securities, Available-for-sale [Line Items]
Marketable securities cost Basis	0	2,125
Gross Unrealized Gains	0	2
Gross Unrealized Losses	0	(15)
Fair value of marketable securities	0	2,112
Cash
Debt Securities, Available-for-sale [Line Items]
Cost Basis	19,746	16,138
Cash and cash equivalents fair value	19,746	16,138
Money market funds | Level 1:
Debt Securities, Available-for-sale [Line Items]
Cost Basis	5,004	5,369
Cash and cash equivalents fair value	$ 5,004	$ 5,369

FAIR VALUE MEASUREMENTS - Addit

FAIR VALUE MEASUREMENTS - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 26, 2018	Dec. 27, 2017	Dec. 28, 2016
Fair Value Disclosures [Abstract]
Impairment charges	$ 0	$ 0	$ 0

FAIR VALUE MEASUREMENTS - Sched

FAIR VALUE MEASUREMENTS - Schedule of Gross Unrealized Losses and Fair Value (Details) - Corporate debt securities - USD ($) $ in Thousands	Dec. 26, 2018	Dec. 27, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value (less than 12 months)	$ 0	$ 1,675
Unrealized Loss (less than 12 months)	0	(12)
Fair Value (12 months or greater)	0	162
Unrealized Loss (12 months or greater)	0	(3)
Fair Value	0	1,837
Unrealized Loss	$ 0	$ (15)

FAIR VALUE MEASUREMENTS - Sch_2

FAIR VALUE MEASUREMENTS - Schedule of Income for AFS Securities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 26, 2018	Dec. 27, 2017	Dec. 28, 2016
Fair Value Disclosures [Abstract]
Dividend income	$ 1,392	$ 830	$ 296
Interest income	9	77	88
Loss on investments	(3)	(5)	(7)
Accumulated Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Net of Tax		(74)
Available-for-sale Securities, Gross Unrealized Loss	(61)
Total other income, net	$ 1,337	$ 902	$ 377

FAIR VALUE MEASUREMENTS - Sch_3

FAIR VALUE MEASUREMENTS - Schedule of AFS Sold (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 26, 2018	Dec. 27, 2017	Dec. 28, 2016
Available-for-sale securities:
Gross proceeds from sales and redemptions		$ 2,144	$ 2,223	$ 938
Cost basis of sales and redemptions		2,160	2,271	956
Gross realized gains included in net income		2	1	2
Gross realized losses included in net income		(18)	(49)	(20)
Amounts reclassified out of accumulated other comprehensive loss	[1]	$ 16	$ 47	$ 19
[1]	Net of tax benefit of $0 for fiscal years ended December 26, 2018, December 27, 2017 and December 28, 2016.

ACCOUNTS RECEIVABLE - Schedule

ACCOUNTS RECEIVABLE - Schedule of Accounts Receivable (Details) - USD ($) $ in Thousands	Dec. 26, 2018	Dec. 27, 2017
Receivables [Abstract]
Landlord receivables	$ 4,494	$ 1,660
Licensing receivables	2,579	1,422
Credit card receivables	2,446	2,018
Other receivables	1,004	541
Accounts receivable	$ 10,523	$ 5,641

ACCOUNTS RECEIVABLE - Addition

ACCOUNTS RECEIVABLE - Additional Information (Details) - USD ($)	Dec. 26, 2018	Dec. 27, 2017
Receivables [Abstract]
Allowance for doubtful accounts	$ 0	$ 0

INVENTORIES - Schedule of Inven

INVENTORIES - Schedule of Inventories (Details) - USD ($) $ in Thousands	Dec. 26, 2018	Dec. 27, 2017
Inventory [Line Items]
Inventories	$ 1,749	$ 1,258
Food
Inventory [Line Items]
Inventories	1,291	874
Wine
Inventory [Line Items]
Inventories	83	69
Beer
Inventory [Line Items]
Inventories	95	85
Beverages
Inventory [Line Items]
Inventories	203	111
Retail merchandise
Inventory [Line Items]
Inventories	$ 77	$ 119

PROPERTY AND EQUIPMENT (Details

PROPERTY AND EQUIPMENT (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 26, 2018	Dec. 27, 2017	Dec. 28, 2016
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 347,301	$ 245,350
Less: accumulated depreciation	(85,447)	(58,255)
Property and equipment, net	261,854	187,095
Depreciation	29,000	21,704	$ 14,502
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	228,453	166,963
Landlord funded assets
Property, Plant and Equipment [Line Items]
Property and equipment, gross	15,595	7,472
Equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	40,716	31,608
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property and equipment, gross	14,055	10,128
Computer equipment and software
Property, Plant and Equipment [Line Items]
Property and equipment, gross	19,008	12,721
Construction in progress (includes assets under construction from deemed landlord financing)
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 29,474	$ 16,458

SUPPLEMENTAL BALANCE SHEET IN_3

SUPPLEMENTAL BALANCE SHEET INFORMATION (Details) - USD ($) $ in Thousands	Dec. 26, 2018	Dec. 27, 2017
Supplemental Balance Sheet Disclosures [Abstract]
Sales tax payable	$ 3,143	$ 1,813
Current portion of liabilities under tax receivable agreement	5,804	937
Gift card liability	1,796	1,472
Other	3,287	3,715
Other current liabilities	$ 14,030	$ 7,937

DEBT (Details)

DEBT (Details) - USD ($)	Feb. 04, 2015	May 31, 2016	Dec. 26, 2018	Dec. 27, 2017	Dec. 28, 2016	Mar. 31, 2013
Debt Instrument [Line Items]
Deemed landlord financing			$ 20,846,000	$ 14,518,000
Interest costs incurred			2,572,000	1,806,000	$ 374,000
Interest costs capitalized			157,000	164,000	$ 0
Notes payable
Debt Instrument [Line Items]
Notes payable face amount						$ 313,000
Notes payable				0
Revolving Credit Facility | Line of credit
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 50,000,000
Current borrowing capacity	$ 20,000,000
Term to maturity	5 years
Short-term borrowings			0	$ 0
Remaining borrowing capacity			19,317,000
Revolving Credit Facility | Letter of credit | Line of credit
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 10,000,000
Current borrowing capacity			$ 683,000
Revolving Credit Facility | Minimum | Line of credit | London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Basis spread on variable rate		2.30%
Revolving Credit Facility | Minimum | Line of credit | Prime rate
Debt Instrument [Line Items]
Basis spread on variable rate		0.00%
Revolving Credit Facility | Maximum | Line of credit | London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Basis spread on variable rate		3.30%
Revolving Credit Facility | Maximum | Line of credit | Prime rate
Debt Instrument [Line Items]
Basis spread on variable rate		0.80%

LEASES - Summary of Rent Expens

LEASES - Summary of Rent Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 26, 2018	Dec. 27, 2017	Dec. 28, 2016
Leases [Abstract]
Minimum rent	$ 24,920	$ 20,421	$ 15,408
Deferred rent	1,241	838	2,122
Contingent rent	4,805	4,902	4,294
Total rent expense	$ 30,966	$ 26,161	$ 21,824

LEASES - Narrative (Details)

LEASES - Narrative (Details) $ in Thousands	12 Months Ended
	Dec. 26, 2018USD ($)lease	Dec. 27, 2017USD ($)lease	Dec. 28, 2016USD ($)
Leases [Abstract]
Number of sale leaseback transactions, accounting owner | lease	24	23
Common area maintenance costs, real estate taxes, and other occocupancy costs not included in rent expense | $	$ 6,479	$ 4,570	$ 3,229
Number of sale leaseback transactions | lease	1	11
Deemed landlord financing | $	$ 20,846	$ 14,518

LEASES - Schedule of Future Min

LEASES - Schedule of Future Minimum Lease Payments (Details) $ in Thousands	12 Months Ended
	Dec. 26, 2018USD ($)lease	Dec. 27, 2017lease
Operating Leases
2,018	$ 31,785
2,019	32,819
2,020	33,363
2,021	33,934
2,022	33,588
Thereafter	174,145
Total minimum lease payments	339,634
Deemed Landlord Financing
2,018	4,487
2,019	4,755
2,020	4,816
2,021	4,889
2,022	5,085
Thereafter	22,659
Total minimum lease payments	$ 46,691
Number of sale leaseback transactions | lease	1	11

EMPLOYEE BENEFIT PLANS - Deferr

EMPLOYEE BENEFIT PLANS - Deferred Compensation (Details) - Executive - Deferred Bonus - USD ($)	12 Months Ended
	Dec. 27, 2017	Dec. 28, 2016	Dec. 25, 2013
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Deferred compensation award due to executive			$ 2,450,000
Deferred compensation expense	$ 0	$ 0	$ 2,054,000

EMPLOYEE BENEFIT PLANS - Define

EMPLOYEE BENEFIT PLANS - Defined Contribution Plan (Details) - USD ($)	12 Months Ended
	Dec. 26, 2018	Dec. 27, 2017	Dec. 28, 2016
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	$ 509,000	$ 389,000	$ 257,000
Defined Contribution Plan, Initial Contribution
Defined Benefit Plan Disclosure [Line Items]
Employer matching contribution percentage	100.00%
Employer matching contribution as a percent of employees' gross pay	3.00%
Defined Contribution Plan, Additional Contribution
Defined Benefit Plan Disclosure [Line Items]
Employer matching contribution percentage	50.00%
Employer matching contribution as a percent of employees' gross pay	3.00%
Defined Contribution Plan, Additional Contribution | Maximum
Defined Benefit Plan Disclosure [Line Items]
Employer matching contribution as a percent of employees' gross pay	5.00%

STOCKHOLDER'S EQUITY (Details)

STOCKHOLDER'S EQUITY (Details)	Feb. 04, 2015	Dec. 26, 2018$ / sharesshares	Dec. 27, 2017$ / sharesshares
Class of Stock [Line Items]
Preferred stock, shares authorized (in shares)		10,000,000	10,000,000
LLC interests acquired (in shares)		2,692,660	1,003,585
Class A Common Stock
Class of Stock [Line Items]
Common stock, shares, issued (in shares)		29,520,833	26,527,477
Common stock, shares authorized (in shares)		200,000,000	200,000,000
Common stock par value (in dollars per share) | $ / shares		$ 0.001	$ 0.001
Ratio of common stock to limited liability company interest	1
Class B Common Stock
Class of Stock [Line Items]
Common stock, shares, issued (in shares)		7,557,347	10,250,007
Common stock, shares authorized (in shares)		35,000,000	35,000,000
Common stock par value (in dollars per share) | $ / shares		$ 0.001	$ 0.001
Common stock | Class A Common Stock
Class of Stock [Line Items]
Redemptions (in shares)		2,692,660	1,003,585
Common stock | Class B Common Stock
Class of Stock [Line Items]
Effect of redemption (in shares)		2,692,660	1,003,585
Limited Liability Company
Class of Stock [Line Items]
Number of units redeemed (in shares)		2,692,660	1,003,585
LLC interests acquired (in shares)		2,993,356
Stock options
Class of Stock [Line Items]
LLC interests acquired (in shares)		300,696	372,508

NON-CONTROLLING INTERESTS - Nar

NON-CONTROLLING INTERESTS - Narrative (Details)	Feb. 04, 2015	Dec. 26, 2018shares	Dec. 27, 2017shares
Noncontrolling Interest [Line Items]
Weighted average ownership percentage		23.40%	29.40%
Units acquired during the period (in shares)		2,692,660	1,003,585
Ownership percent of noncontrolling interest		79.60%	72.10%
Class A Common Stock
Noncontrolling Interest [Line Items]
Ratio of common stock to limited liability company interest	1
Limited Liability Company
Noncontrolling Interest [Line Items]
Units acquired during the period (in shares)		2,993,356
Number of units redeemed (in shares)		2,692,660	1,003,585
Stock options
Noncontrolling Interest [Line Items]
Units acquired during the period (in shares)		300,696	372,508

NON-CONTROLLING INTERESTS - Own

NON-CONTROLLING INTERESTS - Ownership Interest in SSE Holdings (Details) - shares	Dec. 26, 2018	Dec. 27, 2017
Noncontrolling Interest [Abstract]
Number of LLC Interests held by Shake Shack Inc. (in shares)	29,520,833	26,527,477
Number of LLC Interests held by Shake Shack Inc. (in percentage)	79.60%	72.10%
Number of LLC Interests held by non-controlling interest holders (in shares)	7,557,347	10,250,007
Number of LLC Interests held by non-controlling interest holders (in percentage)	20.40%	27.90%
Total LLC Interests outstanding (in shares)	37,078,180	36,777,484
Total LLC Interests outstanding (in percentage)	100.00%	100.00%

NON-CONTROLLING INTERESTS - Sch

NON-CONTROLLING INTERESTS - Schedule of Non-Controlling Interest (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 26, 2018	Sep. 26, 2018	Jun. 27, 2018	Mar. 28, 2018	Dec. 27, 2017	Sep. 27, 2017	Jun. 28, 2017	Mar. 29, 2017	Dec. 26, 2018	Dec. 27, 2017	Dec. 28, 2016
Noncontrolling Interest [Line Items]
Net income (loss) attributable to Shake Shack Inc.	$ (958)	$ 5,025	$ 7,604	$ 3,508	$ (12,463)	$ 4,997	$ 4,879	$ 2,267	$ 15,179	$ (320)	$ 12,446
Other comprehensive loss:
Unrealized holding gains (losses) on available-for-sale securities									13	(47)	(16)
Total effect of changes in ownership interest on equity attributable to Shake Shack Inc.									32,900	8,512	30,247
Unrealized holding gains (losses) on available-for-sale securities
Other comprehensive loss:
Unrealized holding gains (losses) on available-for-sale securities									10	(34)	(10)
Stock options
Other comprehensive loss:
Transfers (to) from non-controlling interests									2,509	4,451	825
Increase in additional paid-in capital as a result of the redemption of LLC Interests
Other comprehensive loss:
Transfers (to) from non-controlling interests									$ 15,202	$ 4,415	$ 16,986

EQUITY-BASED COMPENSATION - Sch

EQUITY-BASED COMPENSATION - Schedule of compensation expense recognized (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 26, 2018	Dec. 27, 2017	Dec. 28, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity-based compensation expense	$ 6,143	$ 5,623	$ 5,354
Total income tax benefit recognized related to equity-based compensation	172	198	168
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity-based compensation expense	3,039	3,474	4,262
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity-based compensation expense	2,449	1,869	1,092
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity-based compensation expense	655	280	0
General and administrative expenses
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity-based compensation expense	5,991	5,463	5,260
Labor and related expenses
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity-based compensation expense	$ 152	$ 160	$ 94

EQUITY-BASED COMPENSATION - Nar

EQUITY-BASED COMPENSATION - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	12 Months Ended
	Jan. 31, 2015	Dec. 26, 2018	Dec. 27, 2017	Dec. 28, 2016	Dec. 30, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity based compensation		$ 107	$ 109	$ 139
Equity-based compensation expense		6,143	5,623	5,354
Proceeds from stock option exercises		5,472	7,585	3,194
Restricted Class B units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity-based compensation expense		655	$ 280	0
Stock options outstanding (in shares)			0
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity-based compensation expense		3,039	$ 3,474	4,262
Fair value vested		3,483	4,458	4,678
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity-based compensation expense		$ 2,449	$ 1,869	$ 1,092
2015 Incentive Award Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares available for grant (in shares)	5,865,522
2015 Incentive Award Plan | Minimum | Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	1 year
2015 Incentive Award Plan | Maximum | Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	5 years
Unit Appreciation Rights Plan | Unit appreciation rights
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options outstanding (in shares)			0
2015 Incentive Award Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options outstanding (in shares)		1,360,983	1,719,341	2,364,722	2,574,981
Unrecognized compensation expense		$ 3,335
Weighted-average period for recognition compensation expense		1 year 2 months 20 days
Intrinsic value of stock options exercised		$ 14,798
Stock option exercises (in shares)		260,515	359,011	160,230
Proceeds from stock option exercises		$ 5,472
2015 Incentive Award Plan | Restricted Class B units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance shares granted (in shares)		49,723	44,476	0
Granted (in shares)		18,882	44,476	0
Granted (in USD per share)		$ 49.12	$ 38.98
2015 Incentive Award Plan | Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Intrinsic value of stock options exercised		$ 5,786	$ 8,333	$ 2,536
Vested (in shares)		(404,120)	(503,686)	(562,296)
2015 Incentive Award Plan | Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period		3 years
Weighted-average period for recognition compensation expense		2 years 1 month 26 days
Performance period		1 year
Performance shares granted (in shares)		118,542	124,842	61,600	0
Shares expected to be recognized		$ 2,954
Granted (in shares)		60,437	87,596	63,600
Granted (in USD per share)		$ 58.46	$ 37.90	$ 38.41
Issuance of common stock in settlement of unit appreciation rights		$ 1,726
Weighted average period		3 years 6 months 10 days
2015 Incentive Award Plan | Minimum | Restricted Class B units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period		1 year
2015 Incentive Award Plan | Minimum | Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Range of awards		0.00%
2015 Incentive Award Plan | Maximum | Restricted Class B units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period		5 years
2015 Incentive Award Plan | Maximum | Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Range of awards		125.00%

EQUITY-BASED COMPENSATION - S_2

EQUITY-BASED COMPENSATION - Schedule of Fair Value of Stock Options (Details) - 2015 Incentive Award Plan - Stock options	12 Months Ended
	Dec. 26, 2018	Dec. 27, 2017	Dec. 28, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (years)	7 years 6 months	7 years 6 months	5 years 6 months
Expected volatility	42.50%	44.50%	50.70%
Risk-free interest rate	2.80%	2.10%	1.50%
Dividend yield	0.00%	0.00%	0.00%

EQUITY-BASED COMPENSATION - S_3

EQUITY-BASED COMPENSATION - Schedule of Stock Options (Details) - 2015 Incentive Award Plan - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 26, 2018	Dec. 27, 2017	Dec. 28, 2016
Stock Options
Outstanding at beginning of period (in shares)	1,719,341	2,364,722	2,574,981
Granted (in shares)	5,036	5,150	16,931
Exercised (in shares)	(260,515)	(359,011)	(160,230)
Forfeited (in shares)	(102,879)	(291,520)	(66,960)
Expired (in shares)	0	0	0
Outstanding at end of period (in shares)	1,360,983	1,719,341	2,364,722
Options vested and exercisable at end of period (in shares)	674,247
Options expected to vest (in shares)	686,736
Weighted Average Exercise Price
Outstanding at beginning of period (in USD per share)	$ 21.16	$ 21.10	$ 21
Granted (in USD per share)	39.91	38.91	34.74
Exercised (in USD per share)	21	21.13	21
Forfeited (in USD per share)	(21.27)	(21)	(21)
Expired (in USD per share)	0	0	0
Outstanding at end of period (in USD per share)	21.25	$ 21.16	$ 21.10
Weighted average options vested and exercisable (in USD per share)	21.26
Options expected to vest (in USD per share)	$ 21.25
Aggregate Intrinsic Value
Outstanding at end of period	$ 29,881
Options exercised during period	14,798
Options expected to vest as of December 26, 2018	$ 15,083
Weighted Average Remaining Contractual Life (Years)
Outstanding at end of period	6 years 1 month 14 days
Options exercisable at end of year	6 years 1 month 12 days
Options expected to vest at end of year	6 years 1 month 16 days
Stock options
Stock Options
Nonvested beginning balance (in shares)	1,176,095	1,964,251	2,574,981
Granted (in shares)	5,036	5,150	16,931
Vested (in shares)	(404,120)	(503,686)	(562,296)
Forfeited (in shares)	(90,275)	(289,620)	(65,365)
Nonvested ending balance (in shares)	686,736	1,176,095	1,964,251
Weighted Average Exercise Price
Nonvested, beginning balance (in USD per share)	$ 8.64	$ 8.66	$ 8.53
Granted (in USD per share)	19.86	19.42	16.32
Vested (in USD per share)	8.62	8.85	8.32
Forfeited (in USD per share)	8.59	8.59	8.59
Nonvested, ending balance (in USD per share)	$ 8.74	$ 8.64	$ 8.66
Aggregate Intrinsic Value
Options exercised during period	$ 5,786	$ 8,333	$ 2,536

EQUITY-BASED COMPENSATION - Sto

EQUITY-BASED COMPENSATION - Stock Options Outstanding and Exercisable (Details) - 2015 Incentive Award Plan	12 Months Ended
	Dec. 26, 2018$ / sharesshares
Twenty-One Dollars
Options Outstanding
Number Outstanding (in shares) | shares	1,339,274
Weighted Average Remaining Contractual Life (Years)	6 years 1 month 3 days
Weighted Average Exercise Price (in USD per share) | $ / shares	$ 21
Options Exercisable
Number Exercisable (in shares) | shares	661,694
Weighted Average Remaining Contractual Life (Years)	6 years 1 month 3 days
Weighted Average Exercise Price (in USD per share) | $ / shares	$ 21
Thirty-Four Point Sixty Two Dollars
Options Outstanding
Number Outstanding (in shares) | shares	10,415
Weighted Average Remaining Contractual Life (Years)	7 years 4 months 22 days
Weighted Average Exercise Price (in USD per share) | $ / shares	$ 34.62
Options Exercisable
Number Exercisable (in shares) | shares	10,415
Weighted Average Remaining Contractual Life (Years)	7 years 4 months 22 days
Weighted Average Exercise Price (in USD per share) | $ / shares	$ 34.62
Thirty-Six Point Forty One Dollars
Options Outstanding
Number Outstanding (in shares) | shares	1,108
Weighted Average Remaining Contractual Life (Years)	7 years 10 months 22 days
Weighted Average Exercise Price (in USD per share) | $ / shares	$ 36.41
Options Exercisable
Number Exercisable (in shares) | shares	1,108
Weighted Average Remaining Contractual Life (Years)	7 years 10 months 22 days
Weighted Average Exercise Price (in USD per share) | $ / shares	$ 36.41
Thirty-Eight Point Ninety One Dollars
Options Outstanding
Number Outstanding (in shares) | shares	5,150
Weighted Average Remaining Contractual Life (Years)	8 years 5 months 16 days
Weighted Average Exercise Price (in USD per share) | $ / shares	$ 38.91
Options Exercisable
Number Exercisable (in shares) | shares	1,030
Weighted Average Remaining Contractual Life (Years)	8 years 5 months 16 days
Weighted Average Exercise Price (in USD per share) | $ / shares	$ 38.91
Thirty-Nine Point Ninety-One Dollars [Member]
Options Outstanding
Number Outstanding (in shares) | shares	5,036
Weighted Average Remaining Contractual Life (Years)	9 years 2 months 25 days
Weighted Average Exercise Price (in USD per share) | $ / shares	$ 39.91
Options Exercisable
Number Exercisable (in shares) | shares	0
Weighted Average Exercise Price (in USD per share) | $ / shares	$ 0

EQUITY-BASED COMPENSATION - Sum

EQUITY-BASED COMPENSATION - Summary of Performance and Restricted Stock Activity (Details) - 2015 Incentive Award Plan - $ / shares	12 Months Ended
	Dec. 26, 2018	Dec. 27, 2017	Dec. 28, 2016
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward]
Outstanding at beginning of period (in shares)	124,842	61,600	0
Granted (in shares)	60,437	87,596	63,600
Performance achievement (in shares)	(12,139)	9,545	0
Vested (in shares)	(43,861)	(22,703)	0
Forfeited (in shares)	(10,737)	(11,196)	(2,000)
Expired (in shares)	0	0	0
Outstanding at end of period (in shares)	118,542	124,842	61,600
Stock Options
Outstanding at beginning of period (in USD per share)	$ 38.06	$ 38.41	$ 0
Granted (in USD per share)	58.46	37.90	38.41
Performance achievement (in USD per share)	37.89	38.40	0
Vested (in USD per share)	38.13	38.40	0
Forfeited (in USD per share)	41.28	38.28	38.43
Expired (in USD per share)	0	0	0
Outstanding at end of period (in USD per share)	$ 48.16	$ 38.06	$ 38.41
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward]
Outstanding at beginning of period (in shares)	44,476	0
Granted (in shares)	18,882	44,476	0
Vested (in shares)	(13,635)	0
Forfeited (in shares)	0	0
Expired (in shares)	0	0
Outstanding at end of period (in shares)	49,723	44,476	0
Stock Options
Outstanding at beginning of period (in USD per share)	$ 38.98	$ 0
Granted (in USD per share)	49.12	38.98
Vested (in USD per share)	39.13	0
Forfeited (in USD per share)	0	0
Expired (in USD per share)	0	0
Outstanding at end of period (in USD per share)	$ 42.79	$ 38.98	$ 0

INCOME TAXES - Narrative (Detai

INCOME TAXES - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 26, 2018	Dec. 27, 2017	Dec. 28, 2016
Income Tax Contingency [Line Items]
Income tax expense related to tax cuts and jobs act		$ 138,636,000
Effective income tax rate (percent)	28.80%	94.50%	22.30%
Deferred tax assets, carryforwards, federal	$ 68,658,000
Deferred tax assets, carryforwards, state and local	60,546,000
Net operating loss carryforwards	18,046,000	$ 12,332,000
Additional deferred tax asset recognized, investment in partnership	38,843,000
Reduction in basis due to amortization of deferred tax asset related to the investment in partnership [Line Items]	12,383,000
Valuation allowance	(6,925,000)	(10,114,000)
Additional deferred tax asset recognized, tax receivable agreement	12,495,000
Increase in valuation allowance	3,189,000
Uncertain tax positions	$ 0	0
Percentage of tax benefits due to equity owners	85.00%
Remaining percentage of tax benefits due to equity owners	15.00%
Other income recognized related to reduction of tax receivable agreement liability	$ 0	$ 4,844,000	$ 0
LLC interests acquired (in shares)	2,692,660	1,003,585
Establishment of liabilities under tax receivable agreement		$ 18,973,000	$ 100,063,000
Establishment of liabilities under tax receivable agreement	$ 203,725,000
Current portion of liabilities under tax receivable agreement	5,804,000	$ 937,000
Members' Equity
Income Tax Contingency [Line Items]
Other income recognized related to reduction of tax receivable agreement liability	0
Federal Tax Authority
Income Tax Contingency [Line Items]
Net operating loss carryforwards	16,791,000
State Tax Authority
Income Tax Contingency [Line Items]
Net operating loss carryforwards	4,586,000
Limited Liability Company
Income Tax Contingency [Line Items]
Additional deferred tax asset recognized, investment in partnership	$ 168,451,000
LLC interests acquired (in shares)	2,993,356

INCOME TAXES - Schedule of Com

INCOME TAXES - Schedule of Components of Income before Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 26, 2018	Dec. 27, 2017	Dec. 28, 2016
Income Tax Disclosure [Abstract]
Domestic	$ 21,595	$ 152,204	$ 20,623
Foreign	9,215	8,089	7,873
Income before income taxes	$ 30,810	$ 160,293	$ 28,496

INCOME TAXES - Schedule of Comp

INCOME TAXES - Schedule of Components of Income Tax Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 26, 2018	Dec. 27, 2017	Dec. 28, 2016
Current income taxes:
Federal	$ 5,281	$ 518	$ 3,767
State and local	858	3,615	2,439
Foreign	1,935	942	667
Total current income taxes	8,074	5,075	6,873
Deferred income taxes:
Federal	(210)	145,139	(48)
State and local	998	1,195	(475)
Total deferred income taxes	788	146,334	(523)
Income tax expense	$ 8,862	$ 151,409	$ 6,350

INCOME TAXES - Reconciliation o

INCOME TAXES - Reconciliation of Income Tax Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 26, 2018	Dec. 27, 2017	Dec. 28, 2016
Income Tax Disclosure [Abstract]
Income taxes at U.S. federal statutory rate	$ 6,470	$ 56,103	$ 9,689
U.S. federal statutory income tax rate, percentage	21.00%	35.00%	34.00%
State and local income taxes, net of federal benefit	$ 797	$ 2,590	$ 1,461
State and local income taxes, net of federal benefit, percentage	2.60%	1.60%	5.10%
Foreign withholding taxes	$ 1,935	$ 942	$ 667
Foreign withholding taxes, percentage	6.30%	0.60%	2.30%
Tax credits	$ (2,151)	$ (1,230)	$ (779)
Tax credits, percentage	(7.00%)	(0.80%)	(2.70%)
Non-controlling interest	$ (1,908)	$ (3,273)	$ (3,765)
Non-controlling interest, percentage	(6.20%)	(2.00%)	(13.20%)
Remeasurement of deferred tax assets in connection with the enactment of the TCJA	$ 0	$ 138,636	$ 0
Remeasurement of deferred tax assets in connection with the enactment of the TCJA, percentage	0.00%	86.50%	0.00%
Remeasurement of deferred tax assets in connection with other tax rate changes	$ 3,794	$ 1,657	$ (1,353)
Remeasurement of deferred tax assets in connection with other tax rate changes, percentage	12.30%	1.00%	(4.70%)
Remeasurement of liabilities under tax receivable agreement in connection with the enactment of the TCJA	$ 0	$ (44,051)	$ 0
Remeasurement of tax receivable agreement liability in connection with the enactment of the TCJA, percentage	(0.00%)	(27.40%)	(0.00%)
Other	$ (75)	$ 35	$ 430
Other, percentage	(0.20%)	0.00%	1.50%
Income tax expense	$ 8,862	$ 151,409	$ 6,350
Effective income tax rate, percentage	28.80%	94.50%	22.30%

INCOME TAXES- Schedule of Defer

INCOME TAXES- Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 26, 2018	Dec. 27, 2017
Income Tax Disclosure [Abstract]
Deferred Tax Asset, Valuation Allowance, Other	$ 733
Deferred Tax Asset, Valuation Allowance, Tax Credit	(6,192)
Deferred tax assets:
Investment in partnership	168,451	$ 137,449
Tax Receivable Agreement	57,203	43,464
Deferred rent	1,109	571
Deferred revenue	184	59
Stock-based compensation	375	322
Net operating loss carryforwards	18,046	12,332
Tax credits	5,194	2,328
Other assets	331	176
Total gross deferred tax assets	250,893	196,701
Valuation allowance	(6,925)	(10,114)
Total deferred tax assets, net of valuation allowance	243,968	186,587
Deferred tax liabilities:
Property and equipment	(1,435)	(673)
Total gross deferred tax liabilities	(1,435)	(673)
Net deferred tax assets	$ 242,533	$ 185,914

EARNINGS PER SHARE - Schedule o

EARNINGS PER SHARE - Schedule of Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 26, 2018	Sep. 26, 2018	Jun. 27, 2018	Mar. 28, 2018	Dec. 27, 2017	Sep. 27, 2017	Jun. 28, 2017	Mar. 29, 2017	Dec. 26, 2018	Dec. 27, 2017	Dec. 28, 2016
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income	$ (548)	$ 6,946	$ 10,571	$ 4,979	$ (11,032)	$ 7,870	$ 8,184	$ 3,682	$ 21,948	$ 8,884	$ 22,146
Less: net income attributable to non-controlling interests									6,769	9,204	9,700
Net income (loss) attributable to Shake Shack Inc.	$ (958)	$ 5,025	$ 7,604	$ 3,508	$ (12,463)	$ 4,997	$ 4,879	$ 2,267	$ 15,179	$ (320)	$ 12,446
Denominator:
Weighted-average shares of Class A common stock outstanding—basic (shares)									28,299	25,876	22,956
Effect of dilutive securities:
Weighted-average shares of Class A common stock outstanding—diluted (shares)									29,179	25,876	23,449
Earnings per share of Class A common stock—basic (in dollars per share)									$ 0.54	$ (0.01)	$ 0.54
Earnings per share of Class A common stock—diluted (in dollars per share)									$ 0.52	$ (0.01)	$ 0.53
Stock options
Effect of dilutive securities:
Restricted Class B units (shares)									798	0	491
Performance Shares
Effect of dilutive securities:
Restricted Class B units (shares)									63		2
Restricted Stock [Member]
Effect of dilutive securities:
Restricted Class B units (shares)									19

EARNINGS PER SHARE - Antidilut

EARNINGS PER SHARE - Antidilutive Securities (Details) (Details) - shares	12 Months Ended
	Dec. 26, 2018	Dec. 27, 2017	Dec. 28, 2016
Stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive shares (in shares)	0	1,719,341	125
Performance Shares
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive shares (in shares)	21,560	124,842	26,860
Restricted Stock Units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive shares (in shares)	0	44,476	0
Class B Common Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive shares (in shares)	7,557,347	10,250,007	11,253,592

SUPPLEMENTAL CASH FLOW INFORM_3

SUPPLEMENTAL CASH FLOW INFORMATION (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 26, 2018	Dec. 27, 2017	Dec. 28, 2016
Cash paid for:
Income taxes, net of refunds	$ 3,272	$ 2,261	$ 1,823
Interest, net of amounts capitalized	2,261	1,106	54
Non-cash investing activities:
Accrued purchases of property and equipment	17,443	7,526	6,150
Capitalized landlord assets for leases where we are deemed the accounting owner	5,443	10,125	1,985
Capitalized equity-based compensation	107	109	139
Non-cash financing activities:
Establishment of liabilities under tax receivable agreement		18,973	100,063
Accrued distributions payable to non-controlling interest holders	0	0	607
Secondary Offering and Redemption of Units | Class A Common Stock
Non-cash investing activities:
Class A common stock issued	2	1	5
Secondary Offering and Redemption of Units | Class B Common Stock
Non-cash financing activities:
Cancellation of Class B common stock	(2)	(1)	(5)
Parent Company | Secondary Offering and Redemption of Units | Class A Common Stock
Non-cash investing activities:
Class A common stock issued	15,202	4,415	18,944
Parent Company | Secondary Offering and Redemption of Units | Class B Common Stock
Non-cash financing activities:
Cancellation of Class B common stock	$ 2	$ 1	$ 5

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Details) - USD ($)	12 Months Ended
	Dec. 26, 2018	Sep. 27, 2017	Dec. 31, 2013
Loss Contingencies [Line Items]
Percentage of tax benefits due to equity owners	85.00%
Establishment of tax receivable agreement liability	$ 203,725,000
Retail site
Loss Contingencies [Line Items]
Letters of credit outstanding	130,000
Office building
Loss Contingencies [Line Items]
Letters of credit outstanding			$ 80,000
Home Office Lease
Loss Contingencies [Line Items]
Letters of credit outstanding		$ 603,000
Former Shake Shack Manager Litigation
Loss Contingencies [Line Items]
Settlement agreement amount funded	$ 1,200,000
IPO
Loss Contingencies [Line Items]
Percentage of tax benefits due to equity owners	85.00%

RELATED PARTY TRANSACTIONS (Det

RELATED PARTY TRANSACTIONS (Details)	12 Months Ended
	Dec. 26, 2018USD ($)renewal_option	Dec. 27, 2017USD ($)	Dec. 28, 2016USD ($)
Related Party Transaction [Line Items]
Percentage of tax benefits due to equity owners	85.00%
Tax receivable agreement amount paid	$ 0	$ 4,844,000	$ 0
Establishment of liabilities under tax receivable agreement	203,725,000
Payments to noncontrolling interests	751,000	2,379,000	1,745,000
Member distributions	0
Rent Expense
Related Party Transaction [Line Items]
Expenses from transactions with related party	877,000	907,000	1,062,000
Daily Provisions
Related Party Transaction [Line Items]
Expenses from transactions with related party		0
Concession Income [Member]
Related Party Transaction [Line Items]
Due from related parties, current	37,000	18,000
Share Our Strength
Related Party Transaction [Line Items]
Expenses from transactions with related party	53,000	148,000	117,000
Related Party Transaction, Amounts of Transaction	20,000
Charitable campaign flow through	343,000	633,000	587,000
Mobo Systems, Inc.
Related Party Transaction [Line Items]
Expenses from transactions with related party	111,000	80,000
Affiliated Entity
Related Party Transaction [Line Items]
General and administrative expenses	2,000	7,000	10,000
Expenses from transactions with related party	0	0
Due from related parties, current	0	0
Affiliated Entity | Self insurance health care expense
Related Party Transaction [Line Items]
Expenses from transactions with related party		0
Hudson Yards Sports and Entertainment
Related Party Transaction [Line Items]
Revenue from Related Parties	$ 420,000	452,000	309,000
Hudson Yards Sports and Entertainment | Concession Income [Member]
Related Party Transaction [Line Items]
Number of renewal terms | renewal_option	5
Renewal option period	5 years
Madison Square Park Conservancy
Related Party Transaction [Line Items]
Expenses from transactions with related party	$ 70,000	0
Madison Square Park Conservancy | Tenant Improvement Allowance
Related Party Transaction [Line Items]
Due from MSP conservancy	0
Other revenues	200,000	0	0
Board of Directors Chairman | Mobo Systems, Inc.
Related Party Transaction [Line Items]
Expenses from transactions with related party		0
Due from MSP conservancy	$ 0	0
Board of Directors Chairman | Square, Inc
Related Party Transaction [Line Items]
Due from MSP conservancy		0
Parent Company
Related Party Transaction [Line Items]
Percentage of tax benefits due to equity owners	85.00%
Tax receivable agreement amount paid	$ 0	4,844,000	$ 0
Establishment of liabilities under tax receivable agreement	203,725,000	159,373,000
Non- Controlling Interest
Related Party Transaction [Line Items]
Tax receivable agreement amount paid	4,910,000	$ 0
Members' Equity
Related Party Transaction [Line Items]
Tax receivable agreement amount paid	$ 0

GEOGRAPHIC INFORMATION (Details

GEOGRAPHIC INFORMATION (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 26, 2018	Sep. 26, 2018	Jun. 27, 2018	Mar. 28, 2018	Dec. 27, 2017	Sep. 27, 2017	Jun. 28, 2017	Mar. 29, 2017	Dec. 26, 2018	Dec. 27, 2017	Dec. 28, 2016
Revenues from External Customers and Long-Lived Assets [Line Items]
TOTAL REVENUE	$ 124,265	$ 119,647	$ 116,282	$ 99,116	$ 96,136	$ 94,609	$ 91,316	$ 76,749	$ 459,310	$ 358,810	$ 268,475
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
TOTAL REVENUE									447,575	348,575	260,602
Other countries
Revenues from External Customers and Long-Lived Assets [Line Items]
TOTAL REVENUE									$ 11,735	$ 10,235	$ 7,873

SELECTED QUARTERLY FINANCIAL _3

SELECTED QUARTERLY FINANCIAL DATA (UNAUDITED) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 26, 2018	Sep. 26, 2018	Jun. 27, 2018	Mar. 28, 2018	Dec. 27, 2017	Sep. 27, 2017	Jun. 28, 2017	Mar. 29, 2017	Dec. 26, 2018	Dec. 27, 2017	Dec. 28, 2016
Quarterly Financial Information Disclosure [Abstract]
TOTAL REVENUE	$ 124,265	$ 119,647	$ 116,282	$ 99,116	$ 96,136	$ 94,609	$ 91,316	$ 76,749	$ 459,310	$ 358,810	$ 268,475
Operating income	2,836	9,343	13,018	6,514	5,838	10,610	11,737	5,628	31,711	33,813	27,805
Net income	(548)	6,946	10,571	4,979	(11,032)	7,870	8,184	3,682	21,948	8,884	22,146
Net income attributable to Shake Shack Inc.	$ (958)	$ 5,025	$ 7,604	$ 3,508	$ (12,463)	$ 4,997	$ 4,879	$ 2,267	$ 15,179	$ (320)	$ 12,446
Earnings (loss) per share
Basic (in dollars per share)	$ (0.03)	$ 0.17	$ 0.27	$ 0.13	$ (0.47)	$ 0.19	$ 0.19	$ 0.09
Diluted (in dollars per share)	$ (0.03)	$ 0.17	$ 0.26	$ 0.13	$ (0.47)	$ 0.19	$ 0.19	$ 0.09

SCHEDULE I_ CONDENSED FINANCI_2

SCHEDULE I: CONDENSED FINANCIAL INFORMATION OF REGISTRANT - BALANCE SHEET (Details) - USD ($) $ / shares in Units, $ in Thousands	Dec. 26, 2018	Dec. 27, 2017	Dec. 28, 2016	Dec. 30, 2015
Preferred stock, par value (in dollars per share)	$ 0	$ 0
Current assets:
Accounts receivable	$ 10,523	$ 5,641
Total current assets	101,119	93,199
Deferred income taxes, net	242,533	185,914
TOTAL ASSETS	610,532	470,606
Current liabilities:
Accrued expenses	22,799	11,649
Current portion of liabilities under tax receivable agreement	5,804	937
Total current liabilities	59,948	34,024
Liabilities under tax receivable agreement, net of current portion	197,921	158,436
Total liabilities	337,077	246,127
Commitments and contingencies
Stockholders' equity:
Preferred stock, no par value—10,000,000 shares authorized; none issued and outstanding as of December 26, 2018 and December 27, 2017, respectively.	0	0
Additional paid-in capital	195,633	153,105
Retained earnings	30,404	16,399
Accumulated other comprehensive loss	0	(49)
Total stockholders' equity	273,455	224,479	$ 201,353	$ 157,019
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	$ 610,532	$ 470,606
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Class A Common Stock
Stockholders' equity:
Common stock	$ 30	$ 27
Common stock par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	200,000,000	200,000,000
Common stock, shares, issued (in shares)	29,520,833	26,527,477
Common stock, shares, outstanding (in shares)	29,520,833	26,527,477
Class B Common Stock
Stockholders' equity:
Common stock	$ 8	$ 10
Common stock par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	35,000,000	35,000,000
Common stock, shares, issued (in shares)	7,557,347	10,250,007
Common stock, shares, outstanding (in shares)	7,557,347	10,250,007
Parent Company
Preferred stock, par value (in dollars per share)	$ 0	$ 0
Current assets:
Cash	$ 5,686	$ 4,988
Accounts receivable	0	0
Prepaid expenses	135	100
Total current assets	5,821	5,088
Deferred income taxes, net	242,353	185,750
Investment in subsidiaries	185,331	142,314
TOTAL ASSETS	433,505	333,152
Current liabilities:
Accrued expenses	171	70
Due to SSE Holdings	3,534	4,217
Current portion of liabilities under tax receivable agreement	5,804	937
Total current liabilities	9,509	5,224
Liabilities under tax receivable agreement, net of current portion	197,921	158,436
Total liabilities	207,430	163,660
Commitments and contingencies
Stockholders' equity:
Preferred stock, no par value—10,000,000 shares authorized; none issued and outstanding as of December 26, 2018 and December 27, 2017, respectively.	0	0
Additional paid-in capital	195,633	153,105
Retained earnings	30,404	16,399
Accumulated other comprehensive loss	0	(49)
Total stockholders' equity	226,075	169,492
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	$ 433,505	$ 333,152
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Parent Company | Class A Common Stock
Stockholders' equity:
Common stock	$ 30	$ 27
Common stock par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	200,000,000	200,000,000
Common stock, shares, issued (in shares)	26,527,477	25,151,384
Common stock, shares, outstanding (in shares)	26,527,477	25,151,384
Parent Company | Class B Common Stock
Stockholders' equity:
Common stock	$ 8	$ 10
Common stock par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	35,000,000	35,000,000
Common stock, shares, issued (in shares)	10,250,007	11,253,592
Common stock, shares, outstanding (in shares)	10,250,007	11,253,592

SCHEDULE I_ CONDENSED FINANCI_3

SCHEDULE I: CONDENSED FINANCIAL INFORMATION OF REGISTRANT - STATEMENTS OF INCOME (LOSS) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 26, 2018	Sep. 26, 2018	Jun. 27, 2018	Mar. 28, 2018	Dec. 27, 2017	Sep. 27, 2017	Jun. 28, 2017	Mar. 29, 2017	Dec. 26, 2018	Dec. 27, 2017	Dec. 28, 2016
Condensed Income Statements, Captions [Line Items]
General and administrative expenses									$ 52,720	$ 39,003	$ 30,556
TOTAL EXPENSES									427,599	324,997	240,670
OPERATING INCOME	$ 2,836	$ 9,343	$ 13,018	$ 6,514	$ 5,838	$ 10,610	$ 11,737	$ 5,628	31,711	33,813	27,805
Other income									78	127,221	688
Interest expense									(2,415)	(1,643)	(374)
INCOME BEFORE INCOME TAXES									30,810	160,293	28,496
Income tax expense									8,862	151,409	6,350
NET INCOME	$ (548)	$ 6,946	$ 10,571	$ 4,979	$ (11,032)	$ 7,870	$ 8,184	$ 3,682	21,948	8,884	22,146
Parent Company
Condensed Income Statements, Captions [Line Items]
Intercompany revenue									2,055	1,466	1,603
Revenues									2,055	1,466	1,603
General and administrative expenses									1,933	1,692	1,603
TOTAL EXPENSES									1,933	1,692	1,603
OPERATING INCOME									122	(226)	0
Equity in net income of subsidiaries									21,537	22,090	16,982
Other income									78	127,221	688
Interest expense									(14)	(50)	(16)
INCOME BEFORE INCOME TAXES									21,723	149,035	17,654
Income tax expense									6,544	149,355	5,208
NET INCOME									$ 15,179	$ (320)	$ 12,446

SCHEDULE I_ CONDENSED FINANCI_4

SCHEDULE I: CONDENSED FINANCIAL INFORMATION OF REGISTRANT - STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (Details) - USD ($)		3 Months Ended								12 Months Ended
		Dec. 26, 2018	Sep. 26, 2018	Jun. 27, 2018	Mar. 28, 2018	Dec. 27, 2017	Sep. 27, 2017	Jun. 28, 2017	Mar. 29, 2017	Dec. 26, 2018	Dec. 27, 2017	Dec. 28, 2016
Condensed Statement of Income Captions [Line Items]
Net income		$ (548,000)	$ 6,946,000	$ 10,571,000	$ 4,979,000	$ (11,032,000)	$ 7,870,000	$ 8,184,000	$ 3,682,000	$ 21,948,000	$ 8,884,000	$ 22,146,000
Available-for-sale Securities:
Change in net unrealized holding (losses)	[1]									(3,000)	(94,000)	(35,000)
Less: reclassification adjustments for net realized losses included in net income	[1]									16,000	47,000	19,000
OTHER COMPREHENSIVE LOSS, NET OF TAX										13,000	(47,000)	(16,000)
COMPREHENSIVE INCOME										21,961,000	8,837,000	22,130,000
Income tax benefit										0	0	0
Parent Company
Condensed Statement of Income Captions [Line Items]
Net income										15,179,000	(320,000)	12,446,000
Available-for-sale Securities:
Change in net unrealized holding (losses)	[1]									(3,000)	(67,000)	(22,000)
Less: reclassification adjustments for net realized losses included in net income	[1]									13,000	33,000	12,000
OTHER COMPREHENSIVE LOSS, NET OF TAX	[1]									10,000	(34,000)	(10,000)
COMPREHENSIVE INCOME										$ 15,189,000	(354,000)	12,436,000
Income tax benefit											$ 0	$ 0
[1]	Net of tax benefit of $0 for fiscal years ended December 26, 2018, December 27, 2017 and December 28, 2016.

SCHEDULE I_ CONDENSED FINANCI_5

SCHEDULE I: CONDENSED FINANCIAL INFORMATION OF REGISTRANT - STATEMENTS OF CASH FLOWS (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 26, 2018	Sep. 26, 2018	Jun. 27, 2018	Mar. 28, 2018	Dec. 27, 2017	Sep. 27, 2017	Jun. 28, 2017	Mar. 29, 2017	Dec. 26, 2018	Dec. 27, 2017	Dec. 28, 2016
OPERATING ACTIVITIES
Net income	$ (548,000)	$ 6,946,000	$ 10,571,000	$ 4,979,000	$ (11,032,000)	$ 7,870,000	$ 8,184,000	$ 3,682,000	$ 21,948,000	$ 8,884,000	$ 22,146,000
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Equity-based compensation									6,143,000	5,623,000	5,354,000
Deferred income taxes									788,000	146,334,000	(523,000)
Other non-cash income									(78,000)	(127,221,000)	(688,000)
Changes in operating assets and liabilities:
Accounts receivable									5,530,000	6,421,000	2,974,000
Prepaid expenses and other current assets									(270,000)	2,244,000	(756,000)
Accrued expenses									7,979,000	4,388,000	5,560,000
Other current liabilities									860,000	(988,000)	2,130,000
NET CASH PROVIDED BY OPERATING ACTIVITIES									85,395,000	70,878,000	54,285,000
INVESTING ACTIVITIES
NET CASH USED IN INVESTING ACTIVITIES									(86,604,000)	(61,943,000)	(114,761,000)
FINANCING ACTIVITIES
Proceeds from stock option exercises									5,472,000	7,585,000	3,194,000
Payments under tax receivable agreement									0	(4,844,000)	0
NET CASH PROVIDED BY FINANCING ACTIVITIES									4,452,000	965,000	1,234,000
INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS									3,243,000	9,900,000	(59,242,000)
CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD				21,507,000				11,607,000	21,507,000	11,607,000	70,849,000
CASH AND CASH EQUIVALENTS AT END OF PERIOD	24,750,000				21,507,000				24,750,000	21,507,000	11,607,000
Parent Company
OPERATING ACTIVITIES
Net income									15,179,000	(320,000)	12,446,000
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Equity in net income of subsidiaries									(21,537,000)	(22,090,000)	(16,982,000)
Equity-based compensation									252,000	234,000	189,000
Non-cash reimbursement revenue treated as investment									0	0	(189,000)
Deferred income taxes									777,000	146,095,000	(462,000)
Other non-cash income									(78,000)	(127,221,000)	(688,000)
Changes in operating assets and liabilities:
Accounts receivable									0	2,000	(2,000)
Prepaid expenses and other current assets									0	5,000	(1,000)
Due to/from SSE Holdings									(7,103,000)	(5,339,000)	214,000
Accrued expenses									5,669,000	21,000	(11,000)
Other current liabilities									14,000	(17,000)	17,000
Income taxes payable									0	2,990,000	5,023,000
NET CASH PROVIDED BY OPERATING ACTIVITIES									(6,827,000)	(5,640,000)	(446,000)
INVESTING ACTIVITIES
Purchases of LLC Interests from SSE Holdings									(11,142,000)	(5,522,000)	(4,559,000)
Return of investment in SSE Holdings									2,053,000	4,101,000	2,694,000
NET CASH USED IN INVESTING ACTIVITIES									(9,089,000)	(1,421,000)	(1,865,000)
FINANCING ACTIVITIES
Proceeds from issuance of Class A common stock to SSE Holdings upon settlement of stock option exercises									11,142,000	5,522,000	2,489,000
Proceeds from stock option exercises									5,472,000	7,586,000	3,185,000
Payments under tax receivable agreement									0	(4,844,000)	0
NET CASH PROVIDED BY FINANCING ACTIVITIES									16,614,000	8,264,000	5,674,000
INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS									698,000	1,203,000	3,363,000
CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD				$ 4,988,000				$ 3,785,000	4,988,000	3,785,000	422,000
CASH AND CASH EQUIVALENTS AT END OF PERIOD	$ 5,686,000				$ 4,988,000				$ 5,686,000	$ 4,988,000	$ 3,785,000

SCHEDULE I_ CONDENSED FINANCI_6

SCHEDULE I: CONDENSED FINANCIAL INFORMATION OF REGISTRANT - NOTES TO FINANCIAL STATEMENTS (Details) - USD ($)	12 Months Ended
	Dec. 26, 2018	Dec. 27, 2017	Dec. 28, 2016
Class of Stock [Line Items]
Percentage of tax benefits due to equity owners	85.00%
Payments under tax receivable agreement	$ 0	$ (4,844,000)	$ 0
Cash paid for:
Income taxes	3,272,000	2,261,000	1,823,000
Interest	2,261,000	1,106,000	54,000
Non-cash financing activities:
Establishment of Liabilities Under Tax Receivable Agreement		18,973,000	100,063,000
Establishment of liabilities under tax receivable agreement	$ 203,725,000
IPO
Class of Stock [Line Items]
Percentage of tax benefits due to equity owners	85.00%
Class A Common Stock | Secondary Offering and Redemption of Units
Non-cash investing activities:
Class A common stock issued	$ 2,000	1,000	5,000
Class B Common Stock | Secondary Offering and Redemption of Units
Non-cash financing activities:
Cancellation of Class B common stock	(2,000)	(1,000)	(5,000)
Parent Company
Class of Stock [Line Items]
Due to SSE Holdings	3,534,000	4,217,000
Intercompany revenue	2,055,000	1,466,000	1,603,000
Equity in net income of subsidiaries	$ 21,537,000	22,090,000	16,982,000
Percentage of tax benefits due to equity owners	85.00%
Payments under tax receivable agreement	$ 0	(4,844,000)	0
Non-cash investing activities:
Accrued contribution related to stock option exercises	5,472,000	7,586,000	1,116,000
Non-cash contribution made in connection with equity awards granted to employees of SSE Holdings	5,999,000	5,497,000	5,304,000
Non-cash financing activities:
Establishment of liabilities under tax receivable agreement	203,725,000	159,373,000
Parent Company | Class A Common Stock | Secondary Offering and Redemption of Units
Non-cash investing activities:
Class A common stock issued	15,202,000	4,415,000	18,944,000
Parent Company | Class B Common Stock | Secondary Offering and Redemption of Units
Non-cash financing activities:
Cancellation of Class B common stock	2,000	1,000	5,000
Consolidation, Eliminations | Parent Company
Class of Stock [Line Items]
Intercompany revenue	2,055,000
Equity in net income of subsidiaries	21,537,000
Cash paid for:
Income taxes	185,000	253,000	576,000
Interest	0	2,000	0
Non-cash financing activities:
Establishment of Liabilities Under Tax Receivable Agreement	$ 44,338,000
Establishment of liabilities under tax receivable agreement		$ 18,973,000	$ 100,063,000

SCHEDULE II_ VALUATION AND QU_2

SCHEDULE II: VALUATION AND QUALIFYING ACCOUNTS (Details) - Deferred tax asset valuation allowance - USD ($) $ in Thousands	12 Months Ended
	Dec. 26, 2018	Dec. 27, 2017	Dec. 28, 2016	Dec. 30, 2015	Dec. 31, 2014
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period	$ 10,114	$ 15,568	$ 23,155	$ 0	$ 0
Charged to costs and expenses	782	0	90	0	0
Charged to other accounts	0	3,455	1,965	39,700	0
Reductions	(3,971)	(8,909)	9,642	16,545	0
Balance at end of period	6,925	$ 10,114	$ 15,568	$ 23,155	$ 0
Reductions related to revaluation of tax reform	$ (4,780)