Series B Convertible Preferred Stock (Details) - USD ($) $ / shares in Units, $ in Thousands, shares in Millions			6 Months Ended
	Mar. 29, 2019	Feb. 03, 2019	Jun. 30, 2019
Redeemable Preferred Shares
Preferred stock dividend rate			3.60%
Authorized shares of preferred stock			5.0
Temporary equity			$ 251,290
Issuance costs			7,250
Dividends paid to preferred shareholders			5,470
Preferred dividends			3,400
Common stock dividends paid to preferred shareholders			2,000
General and administrative expenses
Redeemable Preferred Shares
Temporary equity adjustment			5,600
Series B Preferred Stock
Redeemable Preferred Shares
Temporary equity			251,300
Temporary equity adjustment			5,900
Dividends paid to preferred shareholders			5,400
Preferred dividends			3,400
Common stock dividends paid to preferred shareholders			2,000
Series B Preferred Stock | Franchisee
Redeemable Preferred Shares
Aggregate purchase price of shares	$ 2,500
Temporary equity adjustment			300
Series B Preferred Stock | Securities Purchase Agreement
Redeemable Preferred Shares
Aggregate purchase price of shares	$ 50,000	$ 200,000
Purchase price per share		$ 1,000
Preferred stock dividend rate		3.60%
Conversion rate		$ 50.06
Initial redemption term		8 years
Exchange Cap (as a percent)		19.99%
Issuance costs			7,200
Redemption value		$ 252,500
Series B Preferred Stock | General and administrative expenses
Redeemable Preferred Shares
Aggregate purchase price of shares			50,000
Series B Preferred Stock | General and administrative expenses | Securities Purchase Agreement
Redeemable Preferred Shares
Temporary equity adjustment			$ 5,600