LONG-TERM OBLIGATIONS - Fees and Rates Under Credit Facilities (Details)	12 Months Ended
	Dec. 31, 2017
Consolidated Leverage Ratio: Greater Than Equal To 2.75 to 1.0
Line of Credit Facility [Line Items]
Commitment Fee	0.40%
Letter of Credit Fee	3.00%
Consolidated Leverage Ratio: Greater Than Equal To 2.75 to 1.0 | Minimum [Member]
Line of Credit Facility [Line Items]
Consolidated Leverage Ratio	2.75
Consolidated Leverage Ratio: Greater Than Equal To 2.75 to 1.0 | ABR [Member]
Line of Credit Facility [Line Items]
Margin on Loans	2.00%
Consolidated Leverage Ratio: Greater Than Equal To 2.75 to 1.0 | Eurodollar [Member]
Line of Credit Facility [Line Items]
Margin on Loans	3.00%
Consolidated Leverage Ratio: Less than 2.75 to 1.0 but Greater Than Equal To 1.75 to 1.0
Line of Credit Facility [Line Items]
Commitment Fee	0.35%
Letter of Credit Fee	2.50%
Consolidated Leverage Ratio: Less than 2.75 to 1.0 but Greater Than Equal To 1.75 to 1.0 | Maximum [Member]
Line of Credit Facility [Line Items]
Consolidated Leverage Ratio	2.75
Consolidated Leverage Ratio: Less than 2.75 to 1.0 but Greater Than Equal To 1.75 to 1.0 | Minimum [Member]
Line of Credit Facility [Line Items]
Consolidated Leverage Ratio	1.75
Consolidated Leverage Ratio: Less than 2.75 to 1.0 but Greater Than Equal To 1.75 to 1.0 | ABR [Member]
Line of Credit Facility [Line Items]
Margin on Loans	1.50%
Consolidated Leverage Ratio: Less than 2.75 to 1.0 but Greater Than Equal To 1.75 to 1.0 | Eurodollar [Member]
Line of Credit Facility [Line Items]
Margin on Loans	2.50%
Consolidated Leverage Ratio: Less Than 1.75 to 1.0 but Greater Than Equal To 0.75 to 1.0
Line of Credit Facility [Line Items]
Commitment Fee	0.30%
Letter of Credit Fee	2.00%
Consolidated Leverage Ratio: Less Than 1.75 to 1.0 but Greater Than Equal To 0.75 to 1.0 | Maximum [Member]
Line of Credit Facility [Line Items]
Consolidated Leverage Ratio	1.75
Consolidated Leverage Ratio: Less Than 1.75 to 1.0 but Greater Than Equal To 0.75 to 1.0 | Minimum [Member]
Line of Credit Facility [Line Items]
Consolidated Leverage Ratio	0.75
Consolidated Leverage Ratio: Less Than 1.75 to 1.0 but Greater Than Equal To 0.75 to 1.0 | ABR [Member]
Line of Credit Facility [Line Items]
Margin on Loans	1.00%
Consolidated Leverage Ratio: Less Than 1.75 to 1.0 but Greater Than Equal To 0.75 to 1.0 | Eurodollar [Member]
Line of Credit Facility [Line Items]
Margin on Loans	2.00%
Consolidated Leverage Ratio: Less Than 0.75 to 1.0
Line of Credit Facility [Line Items]
Commitment Fee	0.25%
Letter of Credit Fee	1.50%
Consolidated Leverage Ratio: Less Than 0.75 to 1.0 | Maximum [Member]
Line of Credit Facility [Line Items]
Consolidated Leverage Ratio	0.75
Consolidated Leverage Ratio: Less Than 0.75 to 1.0 | ABR [Member]
Line of Credit Facility [Line Items]
Margin on Loans	0.50%
Consolidated Leverage Ratio: Less Than 0.75 to 1.0 | Eurodollar [Member]
Line of Credit Facility [Line Items]
Margin on Loans	1.50%