CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY/(DEFICIT) - USD ($) $ in Millions	Total	Common Stock	Preferred Stock	Preferred Stock	Preferred Stock Preferred Stock	Common Stock	Common Stock Common Stock	Additional Paid-in Capital	Additional Paid-in Capital Common Stock	Additional Paid-in Capital Preferred Stock	Retained Earnings	Accumulated Other Comprehensive (Loss)/Income	Treasury Stock
Beginning Balance at Sep. 30, 2018	$ 24.5			$ 0.0		$ 0.6		$ 217.8			$ 177.3	$ (241.8)	$ (129.4)
Beginning Balance, Common Stock (in shares) at Sep. 30, 2018						59,608,000
Beginning Balance, Preferred Stock (in shares) at Sep. 30, 2018				0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss)/earnings	70.8										70.8
Share based payments	6.5							6.5
Activity under stock plans	(7.1)							(16.1)			(3.6)		12.6
Activity under stock plans (in shares)						290,000
Dividends to common shareholders	(18.4)										(18.4)
Other comprehensive loss	(5.9)											(5.9)
Ending Balance at Dec. 31, 2018	$ 70.4			$ 0.0		$ 0.6		208.2			226.1	(247.7)	(116.8)
Ending Balance, Common Stock (in shares) at Dec. 31, 2018						59,898,000
Ending Balance, Preferred Stock (in shares) at Dec. 31, 2018				0
Dividends per common share (in dollars per share)	$ 61,400,000
Beginning Balance at Sep. 30, 2018	$ 24.5			$ 0.0		$ 0.6		217.8			177.3	(241.8)	(129.4)
Beginning Balance, Common Stock (in shares) at Sep. 30, 2018						59,608,000
Beginning Balance, Preferred Stock (in shares) at Sep. 30, 2018				0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss from discontinued operations	(12.8)
Deferred compensation plan	0.1
Ending Balance at Jun. 30, 2019	$ 570.7			$ 0.0		$ 0.7		867.2			109.5	(245.3)	(161.4)
Ending Balance, Common Stock (in shares) at Jun. 30, 2019						68,840,000
Ending Balance, Preferred Stock (in shares) at Jun. 30, 2019				2,156,000
Dividends per common share (in dollars per share)	$ 0.30
Beginning Balance at Dec. 31, 2018	$ 70.4			$ 0.0		$ 0.6		208.2			226.1	(247.7)	(116.8)
Beginning Balance, Common Stock (in shares) at Dec. 31, 2018						59,898,000
Beginning Balance, Preferred Stock (in shares) at Dec. 31, 2018				0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss)/earnings	(62.3)										(62.3)
Net loss from discontinued operations	(11.0)										(11.0)
Share based payments	7.6							7.6
Issuance of stock		$ 445.8	$ 199.5				$ 0.1		$ 445.7	$ 199.5
Issuance of stock (in shares)					2,156,000		9,966,000
Activity under stock plans	0.0							(0.5)					0.5
Activity under stock plans (in shares)						11,000
Dividends to common shareholders	(21.6)										(21.6)
Dividends to preferred shareholders	(3.3)										(3.3)
Other comprehensive loss	20.2											20.2
Ending Balance at Mar. 31, 2019	645.3			$ 0.0		$ 0.7		860.5			127.9	(227.5)	(116.3)
Ending Balance, Common Stock (in shares) at Mar. 31, 2019						69,875,000
Ending Balance, Preferred Stock (in shares) at Mar. 31, 2019				2,156,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss)/earnings	9.2										9.2
Net loss from discontinued operations	(1.8)										(1.8)
Share based payments	6.7							6.7
Common stock purchased	(45.0)												(45.0)
Common stock purchased (in shares)						(1,036,000)
Activity under stock plans	(0.1)												(0.1)
Deferred compensation plan	0.1
Activity under stock plans (in shares)						1,000
Dividends to common shareholders	(21.4)										(21.4)
Dividends to preferred shareholders	(4.4)										(4.4)
Other comprehensive loss	(17.8)											(17.8)
Ending Balance at Jun. 30, 2019	570.7			$ 0.0		$ 0.7		867.2			109.5	(245.3)	(161.4)
Ending Balance, Common Stock (in shares) at Jun. 30, 2019						68,840,000
Ending Balance, Preferred Stock (in shares) at Jun. 30, 2019				2,156,000
Beginning Balance at Sep. 30, 2019	543.8			$ 0.0		$ 0.7		870.3			129.5	(298.3)	(158.4)
Beginning Balance, Common Stock (in shares) at Sep. 30, 2019						68,902,000
Beginning Balance, Preferred Stock (in shares) at Sep. 30, 2019				2,156,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss)/earnings	45.8										45.8
Net loss from discontinued operations	0.3										0.3
Share based payments	7.2							7.2
Activity under stock plans	(9.4)							(24.9)			(1.1)		16.6
Activity under stock plans (in shares)						374,000
Dividends to common shareholders	(21.4)										(21.4)
Dividends to preferred shareholders	(4.0)										(4.0)
Other comprehensive loss	25.2											25.2
Ending Balance at Dec. 31, 2019	$ 587.5			$ 0.0		$ 0.7		852.6			149.1	(273.1)	(141.8)
Ending Balance, Common Stock (in shares) at Dec. 31, 2019						69,276,000
Ending Balance, Preferred Stock (in shares) at Dec. 31, 2019				2,156,000
Dividends per common share (in dollars per share)	$ 63,600,000
Beginning Balance at Sep. 30, 2019	$ 543.8			$ 0.0		$ 0.7		870.3			129.5	(298.3)	(158.4)
Beginning Balance, Common Stock (in shares) at Sep. 30, 2019						68,902,000
Beginning Balance, Preferred Stock (in shares) at Sep. 30, 2019				2,156,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss from discontinued operations	(130.3)
Deferred compensation plan	0.3
Ending Balance at Jun. 30, 2020	385.8			$ 0.0		$ 0.7		859.1			10.8	(305.3)	(179.5)
Ending Balance, Common Stock (in shares) at Jun. 30, 2020						68,459,000
Ending Balance, Preferred Stock (in shares) at Jun. 30, 2020				2,156,000
Beginning Balance at Dec. 31, 2019	587.5			$ 0.0		$ 0.7		852.6			149.1	(273.1)	(141.8)
Beginning Balance, Common Stock (in shares) at Dec. 31, 2019						69,276,000
Beginning Balance, Preferred Stock (in shares) at Dec. 31, 2019				2,156,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss)/earnings	13.7										13.7
Net loss from discontinued operations	(131.4)										(131.4)
Share based payments	8.7							8.7
Common stock purchased	(45.0)												(45.0)
Common stock purchased (in shares)						(980,000)
Activity under stock plans	(0.3)							(1.7)			(0.1)		1.5
Deferred compensation plan	0.0							(5.7)					5.7
Deferred compensation plan (in shares)						125,000
Activity under stock plans (in shares)						36,000
Dividends to common shareholders	(21.4)										(21.4)
Dividends to preferred shareholders	(4.1)										(4.1)
Other comprehensive loss	(34.0)											(34.0)
Ending Balance at Mar. 31, 2020	373.7			$ 0.0		$ 0.7		853.9			5.8	(307.1)	(179.6)
Ending Balance, Common Stock (in shares) at Mar. 31, 2020						68,457,000
Ending Balance, Preferred Stock (in shares) at Mar. 31, 2020				2,156,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss)/earnings	29.0										29.0
Net loss from discontinued operations	0.8										0.8
Share based payments	5.3							5.3
Common stock purchased	$ (45.0)
Common stock purchased (in shares)	(980,136)
Activity under stock plans								(0.1)					0.1
Deferred compensation plan	$ 0.5
Activity under stock plans (in shares)						2,000
Dividends to common shareholders	(20.8)										(20.8)
Dividends to preferred shareholders	(4.0)										(4.0)
Other comprehensive loss	1.8											1.8
Ending Balance at Jun. 30, 2020	$ 385.8			$ 0.0		$ 0.7		$ 859.1			$ 10.8	$ (305.3)	$ (179.5)
Ending Balance, Common Stock (in shares) at Jun. 30, 2020						68,459,000
Ending Balance, Preferred Stock (in shares) at Jun. 30, 2020				2,156,000