Significant Accounting Policies - Basis of Presentation (Details)	3 Months Ended	12 Months Ended
	Mar. 31, 2020 item restaurant	Dec. 31, 2019	Jun. 22, 2020 restaurant
Significant Accounting Policies
Length of fiscal year	364 days	364 days
Number of restaurants temporarily closed	33		19
Number of restaurants operating in an off-premise only model	261		81
Number of hourly staff members furloughed | item	41,000