Impairment and other charges, net (Details) $ in Thousands		3 Months Ended		9 Months Ended
		Jul. 08, 2018 USD ($)	Jul. 09, 2017 USD ($) restaurant	Jul. 08, 2018 USD ($) restaurant	Jul. 09, 2017 USD ($) restaurant
Restructuring Cost and Reserve [Line Items]
Restructuring costs		$ 1,872	$ 1,822	$ 4,805	$ 2,252
Accelerated depreciation		538	313	912	691
Losses on disposition of property and equipment, net				(958)	(1,761)
Costs of closed restaurants and other		378	1,934	3,483	4,190
Operating restaurant impairment charges (1)	[1]	0	0	291	0
Impairment and other charges, net		3,265	4,873	10,449	8,894
Restructuring Reserve [Roll Forward]
Restructuring costs		1,872	$ 1,822	4,805	2,252
Q3'17 Acquisition [Member]
Restructuring Reserve [Roll Forward]
Number of restaurants closed | restaurant			3
Property, Plant and Equipment [Member]
Restructuring Reserve [Roll Forward]
Restructuring Costs and Asset Impairment Charges					500
Commitments [Member]
Restructuring Reserve [Roll Forward]
Restructuring Costs and Asset Impairment Charges					500
Restaurant Closing Costs
Restructuring Reserve [Roll Forward]
Other accrued liabilities		2,800		2,800
Qdoba Evaluation retention bonus
Restructuring Cost and Reserve [Line Items]
Restructuring costs		376	$ 0	1,188	0
Restructuring Reserve [Roll Forward]
Restructuring costs		376	0	1,188	0
Qdoba Evaluation consulting costs
Restructuring Cost and Reserve [Line Items]
Restructuring costs	[2]	20	1,654	788	1,654
Restructuring Reserve [Roll Forward]
Restructuring costs	[2]	20	1,654	788	1,654
Employee severance and related costs
Restructuring Cost and Reserve [Line Items]
Restructuring costs		1,476	168	2,828	424
Restructuring Reserve [Roll Forward]
Restructuring Reserve beginning balance				648
Restructuring costs		1,476	168	2,828	424
Cash payments				(2,452)
Restructuring Reserve ending balance		1,024		1,024
Other
Restructuring Cost and Reserve [Line Items]
Restructuring costs		0	0	1	174
Restructuring Reserve [Roll Forward]
Restructuring costs		0	0	1	$ 174
Facility Closing
Restructuring Reserve [Roll Forward]
Restructuring Reserve beginning balance				6,175
Additions				135
Restructuring Reserve, Accrual Adjustment	[3]			648
Cash payments				(4,382)
Restructuring Reserve ending balance	[4],[5]	3,941		3,941
Facility Closing | Interest Expense
Restructuring Reserve [Roll Forward]
Restructuring Reserve, Accrual Adjustment				$ 1,365
Accelerated depreciation
Restructuring Reserve [Roll Forward]
Number of restaurants | restaurant					2
Weighted Average | Facility Closing
Restructuring Reserve [Roll Forward]
Remaining Lease Commitment Term				4
Franchised Units [Member]
Restructuring Reserve [Roll Forward]
Number of restaurants closed | restaurant				4
Entity Operated Units [Member]
Restructuring Reserve [Roll Forward]
Number of restaurants closed | restaurant				1
Continuing Operations [Member]
Restructuring Cost and Reserve [Line Items]
Losses on disposition of property and equipment, net		$ 477	$ 804	$ 958	$ 1,761
Impairment, Disposition, Closing Costs, and Restructuring
Restructuring Reserve [Roll Forward]
Gain (Loss) on Sale of Assets and Asset Impairment Charges				$ 700
Impairment, Disposition, Closing Costs, and Restructuring | Franchised Units [Member]
Restructuring Reserve [Roll Forward]
Number of restaurants closed | restaurant				4
Impairment, Disposition, Closing Costs, and Restructuring | Entity Operated Units [Member]
Restructuring Reserve [Roll Forward]
Number of restaurants closed | restaurant				1
Change in Market Value [Member]
Restructuring Reserve [Roll Forward]
Gain (Loss) on Sale of Assets and Asset Impairment Charges				$ 400

[1] (1)Year-to-date impairment charges are primarily resulting from our landlord’s sale of a restaurant property to a franchisee.

[2] (1)Qdoba Evaluation consulting costs are primarily related to third party advisory services.

[3] (1)Adjustments relate primarily to revisions of certain sublease and cost assumptions. Our estimates related to our future lease obligations, primarily the sublease income we anticipate, are subject to a high degree of judgment and may differ from actual sublease income due to changes in economic conditions, desirability of the sites and other factors

[4] (2)The weighted average remaining lease term related to these commitments is approximately 4 years.

[5] (3)This balance excludes $2.8 million of restaurant closing costs that are included in accrued liabilities and other long-term liabilities on our condensed consolidated balance sheets, which were initially recorded as losses on the sale of company-operated restaurants to Jack in the Box franchisees.