Stock-Based Compensation - Summary of Stock Option and SAR Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Number of Stock Awards
Exercised (in shares)		0
Weighted- Average Exercise Price
Aggregate Intrinsic Value, Exercisable	$ 700
Stock options and SARs
Number of Stock Awards
Beginning Balance (in shares)	4,691,000
Granted at market value (in shares)	0
Exercised (in shares)	(151,000)
Forfeited or expired (in shares)	(169,000)
Ending Balance (in shares)	4,371,000	4,691,000
Exercisable (in shares)	2,992,000
Available for future grants (in shares)	16,347,000
Weighted- Average Exercise Price
Beginning Balance (in dollars per share)	$ 17.41
Granted at market value (in dollars per share)	0.00
Exercised (in dollars per share)	8.24
Forfeited or expired (in dollars per share)	26.99
Ending Balance (in dollars per share)	17.36	$ 17.41
Exercisable (in dollars per share)	$ 18.21
Aggregate Intrinsic Value, Outstanding	$ 4,353
Aggregate Intrinsic Value, Exercisable	$ 2,902
Weighted-Average Remaining Life, Outstanding	2 years 5 months 24 days
Weighted-Average Remaining Life, Exercisable	2 years 5 months 16 days
SARs
Number of Stock Awards
Beginning Balance (in shares)	1,700,000
Ending Balance (in shares)	1,700,000	1,700,000