Share-based Compensation and Equity - Summary of Stock Options Activity (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Options
Outstanding, of period (in shares)	9,903	10,928	11,427
Granted (in shares)	717	4,283	303
Exercised (in shares)	0	0	(245)
Forfeited or expired (in shares)	(1,600)	(5,308)	(557)
Outstanding, end of period (in shares)	9,020	9,903	10,928
Exercisable (in shares)	7,878	8,606	9,004
Vested and expected to vest (in shares)	8,990	9,847	10,790
Weighted Average Exercise Price
Outstanding, beginning of period (in dollars per share)	$ 19.30	$ 21.81	$ 26.12
Granted (in dollars per share)	14.27	19.01	23.29
Exercised (in dollars per share)	0.00	0.00	19.57
Forfeited or expired (in dollars per share)	19.92	18.34	23.78
Outstanding, end of period (in dollars per share)	18.79	19.30	21.81
Exercisable (in dollars per share)	19.11	19.38	21.48
Vested and expected to vest (in dollars per share)	$ 18.80	$ 19.31	$ 21.79
Aggregate Intrinsic Value
Outstanding, beginning of period	$ 0	$ 4,350	$ 20,339
Exercised	0	0	899
Outstanding, end of period	744	0	4,350
Exercisable intrinsic value	265	0	4,350
Vested and expected to vest, intrinsic value	$ 722	$ 0	$ 4,350