Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 4.0	$ 3.6
Current maturities and loan origination fees	4.7	5.1
Debt issuance costs on notes payable	$ 7.0	$ 7.7
Preferred stock, shares authorized (in shares)	300,000.0	300,000.0
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, shares authorized (in shares)	150,000,000	150,000,000
Common stock, shares issued (in shares)	40,400,000	46,200,000
Common stock, shares outstanding (in shares)	40,400,000	46,200,000