Earnings Per Share - Computation of Basic and Diluted Earnings (Loss) Per Share (Details) - USD ($) $ / shares in Units, $ 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
Numerator (both basic and diluted):
Net loss	$ (92,097)	$ (105,642)	$ (265,319)	$ (186,561)	$ (241,700)
Denominator:
Denominator for basic loss per share (in shares)	42,689,773	40,168,406	41,957,755	40,458,557
Denominator for diluted loss per share (in shares)	42,689,773	40,168,406	41,957,755	40,458,557
Basic loss per common share (dollars per share)	$ (2.16)	$ (2.63)	$ (6.32)	$ (4.61)
Diluted loss per common share (dollars per share)	$ (2.16)	$ (2.63)	$ (6.32)	$ (4.61)