Earnings per Common Share Earning per Common Share - Antidilutive Securities (Details) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted-average number of antidilutive potential common shares excluded from computation (in shares)	0	44,377	0	44,833
Series B Convertible Preferred Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted-average number of antidilutive potential common shares excluded from computation (in shares)	0	33,240	0	33,240
Common share warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted-average number of antidilutive potential common shares excluded from computation (in shares)	0	4,513	0	5,196
Employee stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted-average number of antidilutive potential common shares excluded from computation (in shares)	0	5,983	0	5,718
Restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted-average number of antidilutive potential common shares excluded from computation (in shares)	0	641	0	679