CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 2.1	$ 2.3
Preferred stock par value per share (in dollars per share)	$ 0.01	$ 0.01
Preferred stock shares authorized (shares)	20,000,000	20,000,000
Preferred stock shares issued (shares)	1,610,000	0
Preferred stock shares outstanding (shares)	1,610,000	0
Treasury stock (shares)	59,726	0
Common Class A
Common stock par value per share (in dollars per share)	$ 0.01	$ 0.01
Common stock shares authorized (shares)	120,000,000	120,000,000
Common stock shares issued (shares)	13,235,082	12,993,118
Common stock shares outstanding (shares)	13,175,356	12,993,118
Common Class B
Common stock par value per share (in dollars per share)	$ 0.01	$ 0.01
Common stock shares authorized (shares)	60,000,000	60,000,000
Common stock shares issued (shares)	21,485,126	20,449,484
Common stock shares outstanding (shares)	21,485,126	20,449,484