ACQUISITIONS - Summary of Pro Forma Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Total Revenues
As reported	$ 349,796	$ 337,830	$ 1,070,240	$ 805,989
Pro forma (unaudited)		465,094		1,366,820
Operating Income
As reported	(15,307)	(29,432)	(13,716)	(51,021)
Pro forma (unaudited)		(7,339)		(14,678)
Net loss applicable to common shareholders
As reported	$ (46,562)	(49,329)	$ (94,899)	(131,982)
Pro forma (unaudited)		$ (31,034)		$ (95,373)
Net loss per share applicable to common shareholders
As reported, (in dollars per share)	$ (2.59)	$ (2.95)	$ (5.32)	$ (8.49)
Pro forma (unaudited) (in dollars per share)		$ (1.86)		$ (6.13)