星空传媒 Inc. Quarterly report pursuant to Section 13 or 15(d)

PROPERTY, PLANT AND EQUIPMENT (Value Of Each Of The Major Classes Of Consolidated Depreciable Assets) (Details)

PROPERTY, PLANT AND EQUIPMENT (Value Of Each Of The Major Classes Of Consolidated Depreciable Assets) (Details) - USD ($) $ in Millions	Mar. 31, 2018	Jan. 01, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]	听	听	听
Property, plant and equipment, gross	$ 2,091.1	听	$ 2,079.4
Allowance for depreciation and depletion	(1,043.8)	听	(1,028.4)
Property, plant and equipment, net	1,047.3	$ 1,051.0	1,051.0
Land Rights And Mineral Rights [Member]	听	听	听
Property, Plant and Equipment [Line Items]	听	听	听
Property, plant and equipment, gross	549.6	听	549.6
Office And Information Technology [Member]	听	听	听
Property, Plant and Equipment [Line Items]	听	听	听
Property, plant and equipment, gross	66.3	听	66.3
Buildings [Member]	听	听	听
Property, Plant and Equipment [Line Items]	听	听	听
Property, plant and equipment, gross	85.5	听	86.8
Mining Equipment [Member]	听	听	听
Property, Plant and Equipment [Line Items]	听	听	听
Property, plant and equipment, gross	594.0	听	594.4
Processing Equipment [Member]	听	听	听
Property, Plant and Equipment [Line Items]	听	听	听
Property, plant and equipment, gross	619.8	听	617.0
Electric Power Facilities [Member]	听	听	听
Property, Plant and Equipment [Line Items]	听	听	听
Property, plant and equipment, gross	57.0	听	57.0
Land Improvements [Member]	听	听	听
Property, Plant and Equipment [Line Items]	听	听	听
Property, plant and equipment, gross	23.6	听	23.7
Asset Retirement Obligation [Member]	听	听	听
Property, Plant and Equipment [Line Items]	听	听	听
Property, plant and equipment, gross	16.9	听	19.2
Other [Member]	听	听	听
Property, Plant and Equipment [Line Items]	听	听	听
Property, plant and equipment, gross	30.3	听	30.3
Construction in Progress [Member]	听	听	听
Property, Plant and Equipment [Line Items]	听	听	听
Property, plant and equipment, gross	$ 48.1	听	$ 35.1