Consolidated Statements of Operations and Comprehensive Income (Loss) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Statement [Abstract]
Net services revenue ($790.4 million, $600.1 million and $404.4 million from related party for the year ended December 31, 2019, 2018 and 2017, respectively)	$ 1,186.1	$ 868.5	$ 449.8
Operating expenses:
Cost of services	987.8	770.6	416.3
Selling, general and administrative	104.4	97.9	56.3
Other	36.2	30.4	4.7
Total operating expenses	1,128.4	898.9	477.3
Income (loss) from operations	57.7	(30.4)	(27.5)
Loss on debt extinguishment	18.8	0.0	0.0
Net interest expense (income)	29.1	26.3	(0.2)
Income (loss) before income tax provision (benefit)	9.8	(56.7)	(27.3)
Income tax provision (benefit)	(2.2)	(11.4)	31.5
Net income (loss)	$ 12.0	$ (45.3)	$ (58.8)
Net income (loss) per common share:
Basic (in dollars per share)	$ (0.08)	$ (0.60)	$ (0.75)
Diluted (in dollars per share)	$ (0.08)	$ (0.60)	$ (0.75)
Weighted average shares used in calculating net income (loss) per common share:
Basic (in shares)	111,505,993	108,175,159	102,062,051
Diluted (in shares)	111,505,993	108,175,159	102,062,051
Consolidated statements of comprehensive income (loss)
Net income (loss)	$ 12.0	$ (45.3)	$ (58.8)
Other comprehensive loss:
Net change on derivatives designated as cash flow hedges, net of tax	(0.2)	0.5	0.0
Foreign currency translation adjustments	(0.8)	(2.4)	1.2
Comprehensive income (loss)	11.0	(47.2)	(57.6)
Basic:
Net income (loss)	12.0	(45.3)	(58.8)
Less dividends on preferred shares	(20.7)	(19.1)	(17.7)
Net income (loss) available/allocated to common shareholders - basic	(8.7)	(64.4)	(76.5)
Diluted:
Net income (loss)	12.0	(45.3)	(58.8)
Less dividends on preferred shares	(20.7)	(19.1)	(17.7)
Net income (loss) available/allocated to common shareholders - diluted	$ (8.7)	$ (64.4)	$ (76.5)