Share-Based Compensation - Restricted Stock Unit Activity (Details) - Restricted Stock Units (RSUs) - $ / shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Units
Beginning balance (in shares)	747,000	685,000
Granted (in shares)	229,590	250,000
Vested/Paid out (in shares)	(305,000)	(261,000)
Performance Share Units Adjustment (in shares)		73,000
Forfeited/Canceled (in shares)	(2,000)	0
Ending balance (in shares)	670,000	747,000
Grant Date Weighted- Average Fair Value Per Unit
Beginning balance (in dollars per share)	$ 37.91	$ 29.60
Granted (in dollars per share)	55.96	50.37
Vested/Paid out (in dollars per share)	31.39	26.15
Performance Share Units Adjustment (in dollars per share)		27.78
Forfeited/Canceled (in dollars per share)	21.04	0.00
Ending balance (in dollars per share)	$ 47.11	$ 37.91