DEBT, CREDIT FACILITY, AND CAPITAL LEASE OBLIGATIONS (Credit Facility) (Details)	1 Months Ended		12 Months Ended
	Oct. 31, 2016	Oct. 31, 2015 USD ($) credit_extension	Oct. 31, 2021 USD ($)	Dec. 31, 2016 USD ($)	Feb. 15, 2017 USD ($)	Dec. 31, 2010 USD ($)
Line of Credit [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Line of credit facility borrowing capacity		$ 250,000,000
Line of Credit Facility, Number of Extensions Allowed | credit_extension		2
Line of Credit Facility, Extension Period		1 year
Line of Credit Facility, Extension Period, October 2021	1 year
Interest rate spread on LIBOR borrowing				1.00%
Interest rate in addition to alternate base rate for alternate base rate loans				0.00%
Line of Credit Facility, Fair Value of Amount Outstanding				$ 0
Line of Credit [Member] | Revolving Credit Facility [Member] | Subsequent Event [Member]
Debt Instrument [Line Items]
Remaining borrowing capacity					$ 250,000,000
Line of Credit [Member] | Revolving Credit Facility [Member] | Scenario, Forecast [Member]
Debt Instrument [Line Items]
Line of credit facility borrowing capacity			$ 218,000,000
Line of Credit Facility, Extension Period			1 year
Line of Credit [Member] | Revolving Credit Facility Member LOC Sublimit [Member]
Debt Instrument [Line Items]
Line of credit facility borrowing capacity		$ 50,000,000
Line of Credit [Member] | Revolving Credit Facility 2014 and 2010 [Member]
Debt Instrument [Line Items]
Line of credit facility borrowing capacity		270,000,000
Line of Credit [Member] | Term Loan [Member]
Debt Instrument [Line Items]
Line of credit facility borrowing capacity		$ 130,000,000
Letter of Credit [Member]
Debt Instrument [Line Items]
Letter of Credit, Issued in Support of Tax Exempt Bonds						$ 37,000,000
Letter of Credit, Interest Rate at Period End				0.75%