Earnings Per Share - Basic and Diluted Components (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Numerator:
Net (loss) income attributable to common shareholders	$ (13,420)	$ (10,238)	$ (38,354)	$ (30,568)	$ (55,800)	$ (88,600)	$ (62,800)
Denominator:
Weighted average number of common shares outstanding	180,375,680	177,369,017	180,261,449	174,724,746