Impairment and Closure Charges (Details) $ in Thousands		3 Months Ended		9 Months Ended		12 Months Ended
	Jan. 01, 2020	Sep. 30, 2020 USD ($) Restaurant	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($) Restaurant	Sep. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018
Goodwill [Line Items]
Impairment loss				$ 92,200
Long-lived tangible asset impairment		$ 0	$ 0	17,100	$ 0
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201613Member					us-gaap:AccountingStandardsUpdate201613Member	us-gaap:AccountingStandardsUpdate201602Member
Subject to Amortization | Reacquired Franchise Rights
Goodwill [Line Items]
Impairment of intangible assets, finite-lived				3,300
Minimum
Goodwill [Line Items]
Long-lived tangible asset impairment				5
Maximum
Goodwill [Line Items]
Long-lived tangible asset impairment				1,300
Land, Building And Leasehold Improvement [Member]
Goodwill [Line Items]
Long-lived tangible asset impairment				5,900
Revision of Prior Period, Accounting Standards Update, Adjustment
Goodwill [Line Items]
Operating lease, impairment loss						$ 11,200
Accounting Standards Update [Extensible List]							us-gaap:AccountingStandardsUpdate201602Member
Applebee's
Goodwill [Line Items]
Impairment loss				$ 0
Number Of restaurants impacted by long-lived asset impairment | Restaurant		45		45
IHOP
Goodwill [Line Items]
Number Of restaurants impacted by long-lived asset impairment | Restaurant		29		29
Franchised Units | Applebee's
Goodwill [Line Items]
Impairment loss				$ 92,200
Franchised Units | IHOP
Goodwill [Line Items]
Impairment loss				0
Trade Names
Goodwill [Line Items]
Impairment				$ 11,000