CONTINGENCIES AND COMMITMENTS (Detail) - USD ($)	Oct. 10, 2013	Jun. 30, 2016	Dec. 31, 2015
Standby Letters Of Credit [Member]
Loss Contingencies [Line Items]
Letters of credit, outstanding		$ 35,400,000	$ 37,300,000
FinancialStandbyLetterOfCreditMember
Loss Contingencies [Line Items]
Letters of credit, outstanding		13,600,000	$ 14,700,000
Failure to Meet Contractual Obligations [Member]
Loss Contingencies [Line Items]
Damages sought	$ 25,000,000
Surety Bond [Member]
Loss Contingencies [Line Items]
Surety Bond Outstanding		56,000,000
Damage from Fire, Explosion or Other Hazard [Member]
Loss Contingencies [Line Items]
Estimated Litigation Liability		1,000,000,000
Minimum [Member]
Loss Contingencies [Line Items]
Range of possible loss		0
Maximum [Member]
Loss Contingencies [Line Items]
Range of possible loss		$ 53,000,000