Share-Based Compensation Share-based compensation expense (Details) - USD ($) $ in Millions	3 Months Ended				9 Months Ended
	Sep. 30, 2020	[1]	Sep. 30, 2019		Sep. 30, 2020		Sep. 30, 2019
Share-based Compensation Expense [Line Items]
Share-based Payment Arrangement, Expense	$ 3.9		$ 4.1	[2]	$ 11.0	[1]	$ 21.0	[2]
Noncash Share Based Compensation	2.9		5.0	[2]	9.3	[1]	16.2	[2]
Cash Share Based Compensation	1.0		(0.9)	[2]	1.7	[1]	4.8	[2]
Restructuring and related costs incurred in the period			10.4		1.9		37.9
Stock Options [Member]
Share-based Compensation Expense [Line Items]
Share-based Payment Arrangement, Expense	0.0		0.0	[2]	0.0	[1]	0.3	[2]
Restricted Shares [Member]
Share-based Compensation Expense [Line Items]
Share-based Payment Arrangement, Expense	2.9		5.0	[2]	9.3	[1]	15.9	[2]
Restricted Cash Awards [Member]
Share-based Compensation Expense [Line Items]
Share-based Payment Arrangement, Expense	0.5		0.0	[2]	1.2	[1]	0.0	[2]
Performance Share Units [Member]
Share-based Compensation Expense [Line Items]
Share-based Payment Arrangement, Expense	0.5		(0.9)	[2]	0.5	[1]	4.6	[2]
Restricted Share Units (RSUs) [Member]
Share-based Compensation Expense [Line Items]
Share-based Payment Arrangement, Expense	$ 0.0		0.0	[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			1.6		0.5		11.3
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		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		1.5
General and Administrative Expense [Member]
Share-based Compensation Expense [Line Items]
Restructuring and related costs incurred in the period			10.4		1.9		36.7
General and Administrative Expense [Member] | Accelerated Share Based Compensation [Member]
Share-based Compensation Expense [Line Items]
Restructuring and related costs incurred in the period			$ 1.6		$ 0.5		$ 9.8

[1] During the three months ended September 30, 2020, the Company did not incur any costs related to accelerated vesting. During the nine months ended September 30, 2020 the Company incurred $0.5 million 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 nine months ended September 30, 2019, the Company recorded $1.6 million and $11.3 million,

[2] During the three and nine months ended September 30, 2019, the Company recorded $1.6 million and $11.3 million, respectively, of share-based compensation expense related to the acceleration of vesting that occurred as part of the restructuring program. Of the $11.3 million recorded during the nine months ended September 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 $9.8 million is included in the table above. Refer to Note 9 – Restructuring for additional information.