Consolidated Statement of Changes in Shareholder's Equity - USD ($) $ in Millions	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive Income/(Loss)
Beginning Balance at Jun. 30, 2018	$ 1,086.7	$ 1.3	$ 2,283.3	$ (872.1)	$ (325.8)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of change in accounting for ASC 606, net of tax	15.1			15.1
Equity offering, sale of common stock,	445.3	0.1	445.2
Stock Issued During Period, Value, Stock Options Exercised	0.0	0.1	(0.1)
Stock-based compensation	24.1		24.1
Cash paid, in lieu of equity, for tax withholding	(13.3)		(13.3)
Net earnings/(loss)	66.3			66.3
Other comprehensive income/(loss), net of tax	(3.5)				(3.5)
Ending Balance at Mar. 31, 2019	1,620.7	$ 1.5	2,739.2	(790.7)	(329.3)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Equity offering, sale of common stock		11,431,400
Beginning Balance at Dec. 31, 2018	1,563.0	$ 1.5	2,735.1	(822.4)	(351.2)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Equity offering, sale of common stock,	(0.2)		(0.2)
Stock Issued During Period, Value, Stock Options Exercised	0.0
Stock-based compensation	6.6		6.6
Cash paid, in lieu of equity, for tax withholding	(2.3)		(2.3)
Net earnings/(loss)	31.7			31.7
Other comprehensive income/(loss), net of tax	21.9				21.9
Ending Balance at Mar. 31, 2019	1,620.7	$ 1.5	2,739.2	(790.7)	(329.3)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Equity offering, sale of common stock
Beginning Balance at Jun. 30, 2019	1,681.6	$ 1.5	2,757.4	(723.4)	(353.9)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Equity offering, sale of common stock,	494.2	0.1	494.1
Stock Issued During Period, Value, Stock Options Exercised	0.0
Stock-based compensation	35.5		35.5
Cash paid, in lieu of equity, for tax withholding	(25.3)		(25.3)
Non-qualified stock	(0.7)		(0.7)
Dividends, Preferred Stock	24.3			24.3
Net earnings/(loss)	66.5			66.5
Other comprehensive income/(loss), net of tax	(39.7)				(39.7)
Ending Balance at Mar. 31, 2020	2,187.7	$ 1.5	3,261.0	(681.2)	(393.6)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Equity offering, sale of common stock		8,445,900
Beginning Balance at Dec. 31, 2019	1,716.1	$ 1.5	2,759.2	(694.0)	(350.6)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Equity offering, sale of common stock,	494.2	0.1	494.1
Stock Issued During Period, Value, Stock Options Exercised	0.0
Stock-based compensation	8.6		8.6
Cash paid, in lieu of equity, for tax withholding	(0.9)		(0.9)
Dividends, Preferred Stock	8.1			8.1
Net earnings/(loss)	20.9			20.9
Other comprehensive income/(loss), net of tax	(43.0)				(43.0)
Ending Balance at Mar. 31, 2020	$ 2,187.7	$ 1.5	$ 3,261.0	$ (681.2)	$ (393.6)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Equity offering, sale of common stock		8,445,900