Income Taxes - Income Taxes (Narrative) (Details) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2017 USD ($)	Dec. 31, 2018 USD ($) Restaurant	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Income Tax Examination [Line Items]
Changes in tax rates and state tax laws		1.60%	0.30%	1.70%
Goodwill, impairment loss	$ 358.2		$ 358.2
Non-deductibility of goodwill impairment		0.00%	29.30%	0.00%
Deferred tax assets, foreign tax credit carryforward		$ 0.4
Valuation allowance, noncurrent	0.0	0.4	$ 0.0
Operating loss carryforwards	0.6	0.4	0.6
Unrecognized tax benefits	5.9	5.2	5.9	$ 3.9	$ 3.9
Unrecognized tax benefit changes in next 12 months		1.0
Unrecognized tax benefits, interest on income taxes accrued	1.1	1.1	1.1
Unrecognized tax benefits, income tax penalties accrued	$ 0.1	$ 0.1	0.1
Applebee's
Income Tax Examination [Line Items]
Number of restaurants | Restaurant		1,837
Goodwill, impairment loss		$ 358.2
Applebee's | Entity Operated Units
Income Tax Examination [Line Items]
Number of restaurants | Restaurant		69
Goodwill, impairment loss			$ 0.0