Discontinued Operations (Details) - USD ($) $ in Millions	3 Months Ended			6 Months Ended		12 Months Ended
	Jun. 30, 2016	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Loss from discontinued operations, net of income taxes	$ (3.0)	$ (2.4)	$ (36.3)	$ (6.4)	$ (45.2)
Other current assets	2.9	2.9		2.9		$ 3.1
Investments and other assets	13.2	13.2		13.2		13.2
Total assets classified as discontinued operations	16.1	16.1		16.1		16.3
Accounts payable and accrued expenses	20.4	20.4		20.4		60.0
Other noncurrent liabilities	207.4	207.4		207.4		203.7
Total liabilities classified as discontinued operations	$ 227.8	$ 227.8		$ 227.8		263.7
Wilkie Creek [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Charge to discontinued operations					$ 7.6	$ 9.7