Income Taxes - Income Taxes (Narrative) (Details) $ in Millions	3 Months Ended		12 Months Ended
	Jun. 30, 2019 USD ($)	Sep. 30, 2017 USD ($)	Dec. 31, 2019 USD ($) Restaurant	Dec. 31, 2018 USD ($) Restaurant	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Income Tax Examination [Line Items]
Effective Income Tax Rate Reconciliation, Other Reconciling Items, Amount			1.30%	0.20%	0.00%
Changes in tax rates and state tax laws			0.50%	1.60%	0.30%
Goodwill, impairment loss		$ 358.2			$ 358.2
Non-deductibility of goodwill impairment			0.00%	0.00%	29.30%
Deferred tax assets, foreign tax credit carryforward			$ 1.5
Valuation allowance, noncurrent			1.5	$ 0.4
Operating loss carryforwards			0.5	0.4
Unrecognized tax benefits			7.6	5.2	$ 5.9	$ 3.9
Unrecognized tax benefit changes in next 12 months			1.5
Unrecognized tax benefits, interest on income taxes accrued			2.5	1.1
Unrecognized tax benefits, income tax penalties accrued			$ 0.1	$ 0.1
Change in federal tax rate			0.00%	0.00%	15.50%
Applebee's
Income Tax Examination [Line Items]
Number of restaurants | Restaurant			1,787
Goodwill, impairment loss			$ 358.2
Applebee's | Entity Operated Units
Income Tax Examination [Line Items]
Number of restaurants | Restaurant			69	69
Goodwill, impairment loss					$ 0.0
Internal Revenue Service (IRS) [Member]
Income Tax Examination [Line Items]
Proceeds from Income Tax Refunds	$ 13.3
Interest Income, Other	$ 0.9