BASIS OF PRESENTATION Change in Estimate of the Collectability of Accounts Receivable (Details) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2015 USD ($) accounts_receivable	Dec. 31, 2014 Market System
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of large markets | Market		7
Number of legacy billing systems | System		5
Increase in accounts receivable over 180 days	$ 0.7
Increase in allowance for doubtful accounts	$ 5.8
Percentage of allowance for doubtful accounts of total accounts receivable	35.50%	32.10%
Number of types of accounts receivable | accounts_receivable	3