BASIS OF PRESENTATION Change in Estimate of the Collectability of Accounts Receivable (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2015 accounts_receivable	Dec. 31, 2014 Market System
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of large markets		7
Number of legacy billing systems		5
Increase in accounts receivable over 180 days	$ 3.3
Increase in allowance for doubtful accounts	$ 0.3
Percentage of allowance for doubtful accounts of total accounts receivable	32.80%	32.10%
Number of types of accounts receivable	3