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)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Temporary Equity, Carrying Amount, Attributable to Parent	$ 606.6
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
Temporary Equity, Carrying Amount, Attributable to Parent	606.6
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	0.0	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
Temporary Equity, Carrying Amount, Attributable to Parent	606.6
Temporary Equity, Carrying Amount, Attributable to Parent	606.6
Beginning Balance at Jun. 30, 2020	2,898.8	$ 1.6	3,818.7	(535.2)	(386.3)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Equity offering, sale of common stock,	81.8		81.8
Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture	0.0
Stock Issued During Period, Value, Conversion of Convertible Securities	253.0	0.1	252.9
Stock-based compensation	38.5		38.5
Cash paid, in lieu of equity, for tax withholding	(27.8)		(27.8)
APIC, Share-based Payment Arrangement, ESPP, Increase for Cost Recognition	6.2		6.2
APIC, Share-based Payment Arrangement, Option, Increase for Cost Recognition	15.4		15.4
Dividends, Preferred Stock	17.7			17.7
Net earnings/(loss)	402.6			402.6
Other comprehensive income/(loss), net of tax	62.4				62.4
Ending Balance at Mar. 31, 2021	3,713.2	$ 1.7	4,185.7	(150.3)	(323.9)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Temporary Equity, Carrying Amount, Period Increase (Decrease)	(247.6)
Equity offering, sale of common stock		1,162,500
Temporary Equity, Carrying Amount, Attributable to Parent	359.0
Beginning Balance at Dec. 31, 2020	3,455.5	$ 1.7	4,160.8	(377.4)	(329.6)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture	0.0	0.0
Stock-based compensation	8.4		8.4
Cash paid, in lieu of equity, for tax withholding	(1.4)		(1.4)
APIC, Share-based Payment Arrangement, ESPP, Increase for Cost Recognition	2.5		2.5
APIC, Share-based Payment Arrangement, Option, Increase for Cost Recognition	15.4		15.4
Dividends, Preferred Stock	4.7			4.7
Net earnings/(loss)	231.8			231.8
Other comprehensive income/(loss), net of tax	5.7				5.7
Ending Balance at Mar. 31, 2021	3,713.2	$ 1.7	$ 4,185.7	$ (150.3)	$ (323.9)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Temporary Equity, Carrying Amount, Attributable to Parent	$ 359.0