Long-term Compensation Plans - Activity in Payment Awards (Details) - shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Total
Beginning balance (in shares)	3,003,003
Granted (in shares)	1,373,921
Exercised (in shares)	(122,769)
Forfeited (in shares)	(578,429)
Ending balance (in shares)	3,675,726	3,003,003
Stock Options
Beginning balance (in shares)	565,198
Granted (in shares)	256,202	390,198
Exercised (in shares)	(15,319)
Forfeited (in shares)	(73,884)
Ending balance (in shares)	732,197	565,198
Other Than 2013 Plan
Stock Options
Ending balance (in shares)	175,000
RSUs
Equity Classified
Beginning balance (in shares)	2,117,493
Granted (in shares)	1,117,719
Exercised (in shares)	(107,450)
Forfeited (in shares)	(503,911)
Ending balance (in shares)	2,623,851	2,117,493
Liability Classified
Outstanding, beginning balance (in shares)	320,312
Forfeited (in shares)	(634)
Outstanding, ending balance (in shares)	319,678	320,312