SIGNIFICANT ACCOUNTING POLICIES (Landfill Accounting) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2015 USD ($) service_location expansion landfill_site cubic_yard	Dec. 31, 2014 USD ($) cubic_yard	Dec. 31, 2013 USD ($) cubic_yard
Property, Plant and Equipment [Line Items]
Application approvals	5 years
Number of unpermitted expansions | expansion	1
Number of service locations | service_location	1
Percentage of airspace remaining	3.00%
Landfill sites | landfill_site	11
Remaining highly probable airspace	29,786,000
Permitted, but not highly probable airspace	0	0
Remaining Airspace Capacity [Roll Forward]
Remaining capacity, beginning of period (cubic yards)	30,544,000	29,323,000	29,643,000
Addition of highly probable airspace, net (cubic yards)	516,000	2,809,000	1,218,000
Consumed (cubic yards)	(1,274,000)	(1,588,000)	(1,538,000)
Remaining capacity, end of period (cubic yards)	29,786,000	30,544,000	29,323,000
Landfill final closure and post-closure liabilities | $	$ 32.0	$ 29.9
Regulatory post-closure period for landfill	30 years
Inflation rate (as a percent)	1.02%	1.02%
Non-landfill closure and post-closure liabilities | $	$ 24.2	$ 20.8
Senior secured notes | Senior unsecured notes, at 5.25%, due August 1, 2020
Remaining Airspace Capacity [Roll Forward]
Asset retirement obligations discount rate (as a percent)	5.99%	6.54%
Minimum
Remaining Airspace Capacity [Roll Forward]
Non-landfill closure and post-closure liabilities (in years)	10 years
Maximum
Remaining Airspace Capacity [Roll Forward]
Non-landfill closure and post-closure liabilities (in years)	30 years
Permitted
Property, Plant and Equipment [Line Items]
Remaining highly probable airspace	28,906,000
Unpermitted
Property, Plant and Equipment [Line Items]
Remaining highly probable airspace	880,000
Landfill assets
Property, Plant and Equipment [Line Items]
Amortization | $	$ 11.2	$ 14.1	$ 16.8
Non-commercial landfills
Property, Plant and Equipment [Line Items]
Landfill sites | landfill_site	2
Altair | Texas
Property, Plant and Equipment [Line Items]
Remaining lives (years)	6 years
Remaining highly probable airspace	686,000
Altair | Texas | Permitted
Property, Plant and Equipment [Line Items]
Remaining highly probable airspace	686,000
Altair | Texas | Unpermitted
Property, Plant and Equipment [Line Items]
Remaining highly probable airspace	0
Buttonwillow | California
Property, Plant and Equipment [Line Items]
Remaining lives (years)	20 years
Remaining highly probable airspace	7,023,000
Buttonwillow | California | Permitted
Property, Plant and Equipment [Line Items]
Remaining highly probable airspace	7,023,000
Buttonwillow | California | Unpermitted
Property, Plant and Equipment [Line Items]
Remaining highly probable airspace	0
Deer Park | Texas
Property, Plant and Equipment [Line Items]
Remaining lives (years)	7 years
Remaining highly probable airspace	268,000
Deer Park | Texas | Permitted
Property, Plant and Equipment [Line Items]
Remaining highly probable airspace	268,000
Deer Park | Texas | Unpermitted
Property, Plant and Equipment [Line Items]
Remaining highly probable airspace	0
Deer Trail | Colorado
Property, Plant and Equipment [Line Items]
Remaining lives (years)	28 years
Remaining highly probable airspace	1,932,000
Deer Trail | Colorado | Permitted
Property, Plant and Equipment [Line Items]
Remaining highly probable airspace	1,932,000
Deer Trail | Colorado | Unpermitted
Property, Plant and Equipment [Line Items]
Remaining highly probable airspace	0
Grassy Mountain | Utah
Property, Plant and Equipment [Line Items]
Remaining lives (years)	20 years
Remaining highly probable airspace	1,839,000
Grassy Mountain | Utah | Permitted
Property, Plant and Equipment [Line Items]
Remaining highly probable airspace	1,839,000
Grassy Mountain | Utah | Unpermitted
Property, Plant and Equipment [Line Items]
Remaining highly probable airspace	0
Kimball | Nebraska
Property, Plant and Equipment [Line Items]
Remaining lives (years)	9 years
Remaining highly probable airspace	243,000
Kimball | Nebraska | Permitted
Property, Plant and Equipment [Line Items]
Remaining highly probable airspace	243,000
Kimball | Nebraska | Unpermitted
Property, Plant and Equipment [Line Items]
Remaining highly probable airspace	0
Lambton | Ontario
Property, Plant and Equipment [Line Items]
Remaining lives (years)	37 years
Remaining highly probable airspace	5,062,000
Lambton | Ontario | Permitted
Property, Plant and Equipment [Line Items]
Remaining highly probable airspace	5,062,000
Lambton | Ontario | Unpermitted
Property, Plant and Equipment [Line Items]
Remaining highly probable airspace	0
Lone Mountain | Oklahoma
Property, Plant and Equipment [Line Items]
Remaining lives (years)	32 years
Remaining highly probable airspace	4,809,000
Lone Mountain | Oklahoma | Permitted
Property, Plant and Equipment [Line Items]
Remaining highly probable airspace	4,809,000
Lone Mountain | Oklahoma | Unpermitted
Property, Plant and Equipment [Line Items]
Remaining highly probable airspace	0
Ryley | Alberta
Property, Plant and Equipment [Line Items]
Remaining lives (years)	9 years
Remaining highly probable airspace	1,488,000
Ryley | Alberta | Permitted
Property, Plant and Equipment [Line Items]
Remaining highly probable airspace	608,000
Ryley | Alberta | Unpermitted
Property, Plant and Equipment [Line Items]
Remaining highly probable airspace	880,000
Sawyer | North Dakota
Property, Plant and Equipment [Line Items]
Remaining lives (years)	45 years
Remaining highly probable airspace	3,704,000
Sawyer | North Dakota | Permitted
Property, Plant and Equipment [Line Items]
Remaining highly probable airspace	3,704,000
Sawyer | North Dakota | Unpermitted
Property, Plant and Equipment [Line Items]
Remaining highly probable airspace	0
Westmorland | California
Property, Plant and Equipment [Line Items]
Remaining lives (years)	64 years
Remaining highly probable airspace	2,732,000
Westmorland | California | Permitted
Property, Plant and Equipment [Line Items]
Remaining highly probable airspace	2,732,000
Westmorland | California | Unpermitted
Property, Plant and Equipment [Line Items]
Remaining highly probable airspace	0