SPONSORS AND MANAGEMENT WARRANTS (Details) (USD $)	12 Months Ended	1 Months Ended
	Dec. 31, 2012	Feb. 28, 2011	Mar. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Nov. 09, 2010
Sponsors and Management Warrants
Warrant liabilities			$ 474,890,000	$ 366,080,000
Sponsors Warrants [Member]
Sponsors and Management Warrants
Issuance of warrants to purchase common stock (in shares)				1,916,667		8,000,000
Estimated initial value						69,500,000
Exercise price (in dollars per share)						50.00
Warrants exercised	1,525,272
Number of shares of common stock under warrants repurchased	4,558,061
Payments for repurchase of warrants	80,500,000
Additional paid-in capital	108,600,000
Warrant liabilities				203,200,000	157,100,000
Management Warrants [Member]
Sponsors and Management Warrants
Issuance of warrants to purchase common stock (in shares)		2,862,687		2,862,687	2,862,687
Proceeds from issuance of Management warrants		19,000,000
Warrant liabilities				$ 271,700,000	$ 209,000,000
Management Warrants [Member] | Chief Executive Officer [Member]
Sponsors and Management Warrants
Exercise price (in dollars per share)		42.23
Management Warrants [Member] | President [Member]
Sponsors and Management Warrants
Exercise price (in dollars per share)		42.23
Management Warrants [Member] | Chief Financial Officer [Member]
Sponsors and Management Warrants
Exercise price (in dollars per share)		54.50