Net (Loss) Income Per Common Share- Calculation of Basic Net (Loss) Income Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended			9 Months Ended		12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Mar. 31, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Numerator for basic and diluted net (loss) income per share:
Net (loss) income	$ (3,919)	$ (1,299)		$ (71,901)	$ 12,643	$ 3,070
Preferred deemed dividend			$ (9,455)		(9,455)
Series B preferred stock dividends	(4,500)			(13,248)
Net (loss) income attributable to common shareholders	$ (8,419)	$ (1,299)		$ (85,149)	$ 3,188
Denominator for basic net (loss) income per share:
Weighted-average shares outstanding	206,168,035	202,343,245		204,307,431	202,163,250
Weighted-average unvested restricted shares outstanding	(4,197,396)	(1,343,764)		(2,636,314)	(1,336,982)
Denominator for basic net (loss) income per share:	201,970,639	200,999,481		201,671,117	200,826,268
Basic net (loss) income per share attributable to common shareholders	$ (0.04)	$ (0.01)		$ (0.42)	$ 0.02