v3.19.3.a.u2

Property, plant and equipment, net (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Property, plant and equipment, net
Property, plant and equipment, gross	$ 893.7	$ 911.9
Less accumulated depreciation	(391.6)	(362.4)
Total property, plant and equipment, net	502.1	549.5
Depreciation expense	37.6	40.0	$ 83.3
Impairment of property, plant and equipment	4.0	0.0	$ 67.6
Land
Property, plant and equipment, net
Property, plant and equipment, gross	6.4	5.3
Office equipment, machinery and other
Property, plant and equipment, net
Property, plant and equipment, gross	$ 6.5	6.0
Office equipment, machinery and other | Minimum
Property, plant and equipment, net
Depreciable Lives	3 years
Office equipment, machinery and other | Maximum
Property, plant and equipment, net
Depreciable Lives	10 years
Leasehold improvements
Property, plant and equipment, net
Property, plant and equipment, gross	$ 2.1	2.1
Leasehold improvements | Minimum
Property, plant and equipment, net
Depreciable Lives	7 years
Leasehold improvements | Maximum
Property, plant and equipment, net
Depreciable Lives	15 years
Asset retirement obligation.
Property, plant and equipment, net
Property, plant and equipment, gross	$ 23.4	24.1
Asset retirement obligation. | Minimum
Property, plant and equipment, net
Depreciable Lives	1 year
Asset retirement obligation. | Maximum
Property, plant and equipment, net
Depreciable Lives	43 years
Plant in service
Property, plant and equipment, net
Property, plant and equipment, gross	$ 848.1	$ 874.4
Plant in service | Minimum
Property, plant and equipment, net
Depreciable Lives	1 year
Plant in service | Maximum
Property, plant and equipment, net
Depreciable Lives	45 years
Construction in progress
Property, plant and equipment, net
Property, plant and equipment, gross	$ 7.2

X

- Definition

Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

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