CONDENSED CONSOLIDATED BALANCE SHEETS (UNAUDITED) (Parenthetical) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Statement Of Financial Position [Abstract]
Accounts receivable, unbilled services with related parties	$ 1.7	$ 3.8
Accounts payable includes related parties	0.1	0.3
Advanced billings with related parties	$ 0.5	$ 0.4
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock shares authorized	5,000,000	5,000,000
Preferred stock shares issued	0	0
Preferred stock shares outstanding	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock shares authorized	250,000,000	250,000,000
Common stock shares issued	35,728,989	35,665,910
Common stock shares outstanding	35,728,989	35,665,910
Treasury stock shares	200,000	200,000