Basis and Summary of Significant Accounting Policies - Narrative (Details)	3 Months Ended		12 Months Ended
	Mar. 31, 2019 USD ($) state	Mar. 31, 2018 USD ($)	Dec. 31, 2018	Dec. 31, 2017 franchise
Significant Accounting Policies [Line Items]
Number of businesses acquired | franchise				4
Threshold Period Past Due for Write-off of Trade Accounts Receivable			60 days
Progressive Finance Holdings, LLC
Significant Accounting Policies [Line Items]
Threshold Period Past Due for Write-off of Trade Accounts Receivable			120 days
Progressive Leasing
Significant Accounting Policies [Line Items]
Number of states in which entity operates | state	46
Progressive leasing invoice volume | $	$ 394,727	$ 345,562