Long-term Compensation Plans - Activity in Payment Awards (Details) - shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Total
Beginning balance (in shares)	3,675,726
Granted (in shares)	1,581,444
Exercised (in shares)	(988,573)
Canceled (in shares)	(198,313)
Forfeited (in shares)	(179,641)
Ending balance (in shares)	3,890,643	3,675,726
Stock Options
Beginning balance (in shares)	732,197
Granted (in shares)	0	256,202	390,198
Exercised (in shares)	(20,425)
Cancelled (in shares)	(175,000)
Forfeited (in shares)	0
Ending balance (in shares)	536,772	732,197
Other Than 2013 Plan
Stock Options
Ending balance (in shares)	175,000
RSUs
Equity Classified
Beginning balance (in shares)	2,623,851
Granted (in shares)	1,581,444	1,117,719	1,754,868
Exercised (in shares)	(968,148)
Forfeited (in shares)	(179,641)
Cancelled (in shares)	(23,313)
Ending balance (in shares)	3,034,193	2,623,851
Liability Classified
Outstanding, beginning balance (in shares)	319,678
Granted (in shares)	0
Forfeited (in shares)	0
Outstanding, ending balance (in shares)	319,678	319,678