Income Taxes - Temporary Differences (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Jan. 01, 2019	Jan. 02, 2018
Deferred tax assets:
Staff member benefits	$ 27,059	$ 22,925
Insurance reserves	14,157	15,165
Accrued rent	27,582	10,870
Deferred income	22,725	17,288
Stock-based compensation	8,794	8,628
Tax credit carryforwards	15,754	1,880
Other	1,958	1,265
Subtotal	118,029	78,021
Less: Valuation allowance	(713)	(792)
Total	117,316	77,229
Deferred tax liabilities:
Property and equipment	(131,120)	(107,513)
Prepaid expenses	(8,819)	(7,929)
Inventory	(7,713)	(6,893)
Other	(136)	(5,420)
Total	(147,788)	(127,755)
Net deferred tax liability	(30,472)	(50,526)
Reconciliation of beginning and ending amount of our uncertain tax positions
Balance at beginning of year	830	843	$ 829
Additions related to current period tax positions	13	104	168
Reductions related to settlements with taxing authorities and lapses of statutes of limitations	(139)	(117)	(154)
Balance at end of year	704	830	$ 843
Accrued interest and penalties related with uncertain tax positions	200	200
Decrease in uncertain tax positions during the next twelve months based on the lapses of statutes of limitations for certain jurisdictions	0
State
Reconciliation of beginning and ending amount of our uncertain tax positions
Tax credit carryforwards	1,900	2,400
Tax credit carryforward valuation allowance	700	800
Foreign
Deferred tax assets:
Tax credit carryforwards	800
Reconciliation of beginning and ending amount of our uncertain tax positions
Tax credit carryforwards		700
Federal
Deferred tax assets:
Tax credit carryforwards	$ 14,300	$ 3,300