Consolidated Statements of Operations and Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Income Statement [Abstract]
Net services revenue ($199.0 million and $380.8 million for the three and six months ended June 30, 2019, respectively, and $141.9 million and $278.1 million for the three and six months ended June 30, 2018, respectively, from related party)	$ 295.0	$ 207.9	$ 570.9	$ 355.2
Operating expenses:
Cost of services	246.1	189.9	483.3	328.6
Selling, general and administrative	25.8	22.5	48.3	39.5
Other expenses	10.7	13.2	19.5	15.6
Total operating expenses	282.6	225.6	551.1	383.7
Income (loss) from operations	12.4	(17.7)	19.8	(28.5)
Loss on debt extinguishment	(18.8)	0.0	(18.8)	0.0
Net interest (expense) income	(9.9)	(5.8)	(20.1)	(5.6)
Income (loss) before income tax provision (benefit)	(16.3)	(23.5)	(19.1)	(34.1)
Income tax provision (benefit)	(11.1)	(20.6)	(14.1)	(7.9)
Net income (loss)	$ (5.2)	$ (2.9)	$ (5.0)	$ (26.2)
Net income (loss) per common share:
Basic (in dollars per share)	$ (0.09)	$ (0.07)	$ (0.14)	$ (0.33)
Diluted (in dollars per share)	$ (0.09)	$ (0.07)	$ (0.14)	$ (0.33)
Weighted average shares used in calculating net income (loss) per common share:
Basic (in shares)	110,956,014	108,157,583	110,382,509	107,001,002
Diluted (in shares)	110,956,014	108,157,583	110,382,509	107,001,002
Consolidated statements of comprehensive income (loss)
Net income (loss)	$ (5.2)	$ (2.9)	$ (5.0)	$ (26.2)
Other comprehensive income (loss):
Net change on derivatives designated as cash flow hedges, net of tax	0.1	(0.4)	0.3	(0.6)
Foreign currency translation adjustments	0.0	(1.4)	0.5	(1.9)
Comprehensive income (loss)	(5.1)	(4.7)	(4.2)	(28.7)
Basic:
Net income (loss)	(5.2)	(2.9)	(5.0)	(26.2)
Less dividends on preferred shares	(5.1)	(4.8)	(10.1)	(9.4)
Net income (loss) available/allocated to common shareholders - basic	(10.3)	(7.7)	(15.1)	(35.6)
Diluted:
Net income (loss)	(5.2)	(2.9)	(5.0)	(26.2)
Less dividends on preferred shares	(5.1)	(4.8)	(10.1)	(9.4)
Net income (loss) available/allocated to common shareholders - diluted	$ (10.3)	$ (7.7)	$ (15.1)	$ (35.6)