BUSINESS COMBINATION - CONSIDERATION PAID (Details) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended	12 Months Ended
	May. 29, 2015	Mar. 31, 2016	Dec. 31, 2015
Assets acquired and liabilities assumed
Multi-employer withdrawal liabilities		$ (55.5)	$ (56.2)
Goodwill		241.6	241.6
Horizon
Business acquisition
Business Combination, Ownership Percentage	100.00%
Cash price (in dollars per share)	$ 0.72
Assets acquired and liabilities assumed
Cash and cash equivalents		0.8	0.8
Accounts receivable		31.7	31.7
Other current assets		7.2	7.2
Deferred tax assets, net		45.6	45.6
Property and equipment		170.4	170.4
Intangibles - Customer relationships		140.0	140.0
Other long-term assets		4.1	4.1
Accounts payable		(22.8)	(22.8)
Accruals and other current liabilities		(32.1)	(32.1)
Multi-employer withdrawal liabilities		(60.6)	(60.6)
Capital lease obligations		(1.6)	(1.6)
Horizon's debt and warrants		(467.5)	(467.5)
Total identifiable assets less liabilities		(184.8)	(184.8)
Total cash paid for common shares		(29.4)	(29.4)
Goodwill		$ 214.2	$ 214.2
Horizon | As previously Reported
Total cash consideration
Common shares	$ 29.4
Warrants	37.1
Horizon's debt (including accrued interest and breakage fees)	428.9
Total	$ 495.4