DEBT (Revolving Credit Facility) (Details) - USD ($)			12 Months Ended
	Jun. 19, 2015	Oct. 31, 2011	Dec. 31, 2015	Dec. 31, 2016
Line of Credit Facility [Line Items]
Line of Credit Facility, term (in years)	5 years	5 years
Letters of credit issued			$ 2,500,000	$ 3,800,000
Revolving Credit Facility
Line of Credit Facility [Line Items]
Revolving credit facility, maximum borrowing capacity	$ 2,000,000,000	$ 1,000,000,000
Payments of Debt Issuance Costs			4,000,000.0
Line of Credit, Current			0	$ 0
Write off of Deferred Debt Issuance Cost			$ 1,000,000
Letter of Credit
Line of Credit Facility [Line Items]
Revolving credit facility, maximum borrowing capacity	70,000,000
Swingline Loans
Line of Credit Facility [Line Items]
Revolving credit facility, maximum borrowing capacity	$ 50,000,000.0
Minimum | Revolving Credit Facility
Line of Credit Facility [Line Items]
Commitment fee rate	0.085%
Minimum | Rate 2C | Revolving Credit Facility
Line of Credit Facility [Line Items]
Basis spread on variable rate	0.00%
Maximum | Revolving Credit Facility
Line of Credit Facility [Line Items]
Commitment fee rate	0.20%
Maximum | Rate 2C | Revolving Credit Facility
Line of Credit Facility [Line Items]
Basis spread on variable rate	0.50%
London Interbank Offered Rate (LIBOR) | Minimum | Rate 1 | Revolving Credit Facility
Line of Credit Facility [Line Items]
Basis spread on variable rate	0.875%
London Interbank Offered Rate (LIBOR) | Maximum | Rate 1 | Revolving Credit Facility
Line of Credit Facility [Line Items]
Basis spread on variable rate	1.50%
Federal Funds Purchased | Rate 2B | Revolving Credit Facility
Line of Credit Facility [Line Items]
Basis spread on variable rate	0.50%
One Month LIBOR | Rate 2C | Revolving Credit Facility
Line of Credit Facility [Line Items]
Basis spread on variable rate	1.00%