Earnings per Share - Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share (Detail) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Earnings Per Share [Abstract]
Basic weighted average common stock outstanding (in shares)	98,568,971	54,469,943	87,315,661	49,497,353
Potentially Dilutive Securities:
Shares underlying the conversion of preferred stock to common stock	10,414,242	10,476,430	10,447,283	10,485,283
Shares underlying the conversion of the convertible senior notes	4,190,266	7,341,490	4,578,305	7,473,420
Shares underlying warrants to purchase common stock	8,531,604	8,222,305	8,727,799	8,011,371
Shares underlying stock options to purchase common stock	596,422	557,973	627,511	529,072
Shares underlying restricted stock units and performance-based restricted stock units	1,132,326	821,892	1,114,133	713,498
Antidilutive shares excluded from the computation of earnings per share	24,864,860	27,420,090	25,495,031	27,212,644
Diluted weighted average shares outstanding	123,433,831	81,890,033	112,810,692	76,709,997