Consolidated Statements of Operations and Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Income Statement [Abstract]
Net services revenue ($206.4 million and $414.8 million for the three and six months ended June 30, 2020, respectively, and $199.0 million and $380.8 million for the three and six months ended June 30, 2019, respectively, from related party)	$ 314.7	$ 295.0	$ 635.2	$ 570.9
Operating expenses:
Cost of services	248.3	246.1	502.2	483.3
Selling, general and administrative	23.3	25.8	48.8	48.3
Other expenses	18.0	10.7	26.7	19.5
Total operating expenses	289.6	282.6	577.7	551.1
Income from operations	25.1	12.4	57.5	19.8
Loss on debt extinguishment	0.0	18.8	0.0	18.8
Net interest expense	4.8	9.9	8.6	20.1
Income (loss) before income tax provision (benefit)	20.3	(16.3)	48.9	(19.1)
Income tax provision (benefit)	5.2	(11.1)	15.6	(14.1)
Net income (loss)	$ 15.1	$ (5.2)	$ 33.3	$ (5.0)
Net income (loss) per common share:
Basic (in dollars per share)	$ 0.04	$ (0.09)	$ 0.10	$ (0.14)
Diluted (in dollars per share)	$ 0.03	$ (0.09)	$ 0.08	$ (0.14)
Weighted average shares used in calculating net income (loss) per common share:
Basic (in shares)	115,067,552	110,956,014	114,754,298	110,382,509
Diluted (in shares)	165,887,964	110,956,014	167,809,324	110,382,509
Consolidated statements of comprehensive income (loss)
Net income (loss)	$ 15.1	$ (5.2)	$ 33.3	$ (5.0)
Other comprehensive income (loss):
Net change on derivatives designated as cash flow hedges, net of tax	0.8	0.1	(3.6)	0.3
Foreign currency translation adjustments	(0.2)	0.0	(2.3)	0.5
Comprehensive income (loss)	15.7	(5.1)	27.4	(4.2)
Basic:
Net income (loss)	15.1	(5.2)	33.3	(5.0)
Less dividends on preferred shares	(5.6)	(5.1)	(11.0)	(10.1)
Less income allocated to preferred shareholders	(4.7)	0.0	(11.0)	0.0
Net income (loss) available/allocated to common shareholders - basic	4.8	(10.3)	11.3	(15.1)
Diluted:
Net income (loss)	15.1	(5.2)	33.3	(5.0)
Less dividends on preferred shares	(5.6)	(5.1)	(11.0)	(10.1)
Less income allocated to preferred shareholders	(3.8)	0.0	(8.9)	0.0
Net income (loss) available/allocated to common shareholders - diluted	$ 5.7	$ (10.3)	$ 13.4	$ (15.1)