Business and Summary of Significant Accounting Policies - Accounts Receivable Net of Allowances (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable, net of allowances	$ 99,887	$ 95,777
Customers
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable, net of allowances	48,661	36,227
Corporate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable, net of allowances	23,431	26,375
Franchisee
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable, net of allowances	$ 27,795	$ 33,175