Subsequent Events (Details)			9 Months Ended
	Feb. 23, 2016 USD ($) restaurant	Feb. 09, 2016 USD ($)	Jan. 22, 2016 restaurant	Feb. 18, 2016 $ / shares
Subsequent Event [Line Items]
Number of restaurants | restaurant			548
Operating lease initial term			20 years
Cash Dividend Declared
Subsequent Event [Line Items]
Dividends payable, date declared			Feb. 18, 2016
Dividends payable, date to be paid			Mar. 14, 2016
Dividends payable, date of record			Feb. 29, 2016
Subsequent event
Subsequent Event [Line Items]
Number of restaurants | restaurant	145
Subsequent event | Cash Dividend Declared
Subsequent Event [Line Items]
Dividends payable, amount per share | $ / shares				$ 0.34
Mortgages | Subsequent event
Subsequent Event [Line Items]
Mortgage on corporate headquarters		$ 30,000,000
Term of mortgage		10 years
Rate of interest		5.10%
National and Mesirow Sale Leaseback | Subsequent event
Subsequent Event [Line Items]
Selling price	$ 200,000,000
Operating lease initial term	20 years
Rent expense	$ 13,800,000
National | Subsequent event
Subsequent Event [Line Items]
Number of restaurants | restaurant	119
Selling price	$ 163,400,000
Rent escalator	1.50%
Mesirow | Subsequent event
Subsequent Event [Line Items]
Number of restaurants | restaurant	26
Selling price	$ 36,600,000
Rent escalator	1.50%
Minimum | National and Mesirow Sale Leaseback | Subsequent event
Subsequent Event [Line Items]
Net proceeds	$ 165,000,000
Maximum | National and Mesirow Sale Leaseback | Subsequent event
Subsequent Event [Line Items]
Net proceeds	$ 170,000,000