Share-Based Compensation Share-based compensation expense (Details) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2020		Jun. 30, 2019		Jun. 30, 2020		Jun. 30, 2019
Share-based Compensation Expense [Line Items]
Share-based Payment Arrangement, Expense	$ 3.2	[1]	$ 5.2	[2]	$ 7.1	[1]	$ 16.9	[2]
Noncash Share Based Compensation	3.1	[1]	4.8	[2]	6.4	[1]	11.2	[2]
Cash Share Based Compensation	0.1	[1]	0.4	[2]	0.7	[1]	5.7	[2]
Restructuring and related costs incurred in the period	0.5		6.1		1.9		27.5
Stock Options [Member]
Share-based Compensation Expense [Line Items]
Share-based Payment Arrangement, Expense	0.0	[1]	0.0	[2]	0.0	[1]	0.3	[2]
Restricted Shares [Member]
Share-based Compensation Expense [Line Items]
Share-based Payment Arrangement, Expense	3.1	[1]	4.8	[2]	6.4	[1]	10.9	[2]
Restricted Cash Awards [Member]
Share-based Compensation Expense [Line Items]
Share-based Payment Arrangement, Expense	0.5	[1]	0.0	[2]	0.7	[1]	0.0	[2]
Performance Share Units [Member]
Share-based Compensation Expense [Line Items]
Share-based Payment Arrangement, Expense	(0.4)	[1]	0.3	[2]	0.0	[1]	5.5	[2]
Restricted Share Units (RSUs) [Member]
Share-based Compensation Expense [Line Items]
Share-based Payment Arrangement, Expense	0.0	[1]	0.1	[2]	0.0	[1]	0.2	[2]
Accelerated Share Based Compensation [Member]
Share-based Compensation Expense [Line Items]
Restructuring and related costs incurred in the period	0.3		1.3		0.5		9.7
Net gain (loss) from asset sales [Member]
Share-based Compensation Expense [Line Items]
Restructuring and related costs incurred in the period	0.0		0.0		0.0		1.4
Net gain (loss) from asset sales [Member] | Accelerated Share Based Compensation [Member]
Share-based Compensation Expense [Line Items]
Restructuring and related costs incurred in the period	0.0		0.0		0.0		1.5
General and Administrative Expense [Member]
Share-based Compensation Expense [Line Items]
Restructuring and related costs incurred in the period	0.5		6.0		1.9		26.3
General and Administrative Expense [Member] | Accelerated Share Based Compensation [Member]
Share-based Compensation Expense [Line Items]
Restructuring and related costs incurred in the period	$ 0.3		$ 1.3		$ 0.5		$ 8.2

[1] During the three and six months ended June 30, 2020, the Company recorded $0.3 million and $0.5 million, respectively, of share-based compensation expense related to the acceleration of vesting that occurred as part of the restructuring program and is included in the table above. Refer to Note 9 – Restructuring for additional information.(2)During the three and six months ended June 30, 2019, the Company recorded $1.3 million and $9.7 million,

[2] During the three and six months ended June 30, 2019, the Company recorded $1.3 million and $9.7 million, respectively, of share-based compensation expense related to the acceleration of vesting that occurred as part of the restructuring program. Of the $9.7 million recorded during the six months ended June 30, 2019, $1.5 million was recorded in "Net gain (loss) from asset sales, inclusive of restructuring costs" on the statement of operations and the remaining $8.2 million is included in the table above. Refer to Note 9 – Restructuring for additional information.