Long-lived Asset Impairment - Additional Information (Detail) - USD ($) $ in Millions		1 Months Ended	6 Months Ended	9 Months Ended
	Nov. 18, 2015	Jun. 30, 2017	Jun. 30, 2017	Sep. 30, 2017
Impaired Long Lived Assets Held And Used [Line Items]
Contract termination fee received		$ 4.0		$ 4.0
Impairment of long lived assets held for use				$ 170.6
WCS
Impaired Long Lived Assets Held And Used [Line Items]
Impairment of long lived assets held for use			$ 170.6
Property and equipment, salvage value		$ 5.7	5.7
WCS | Net Property and Equipment
Impaired Long Lived Assets Held And Used [Line Items]
Impairment of long lived assets held for use			127.5
WCS | Disposal Site Operating Permits, Net
Impaired Long Lived Assets Held And Used [Line Items]
Impairment of long lived assets held for use			42.0
WCS | Other Asset
Impaired Long Lived Assets Held And Used [Line Items]
Impairment of long lived assets held for use			$ 1.1
WCS | Divestiture Terms Previously Pending
Impaired Long Lived Assets Held And Used [Line Items]
Proceeds from sale of subsidiary	$ 270.0