Shareholders' Equity and Stock Incentive Plans (Summary of SARs Activity) (Details) - Stock Appreciation Rights (SARs) [Member] $ / shares in Units, $ in Millions	6 Months Ended
	Jun. 30, 2018 USD ($) $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward]
SARs, Outstanding, Beginning of period | shares	714,238
SARs, Granted | shares	616,686
SARs, Exercised | shares	0
SARs, Forfeitures | shares	0
SARs, Expirations | shares	0
SARs, Outstanding, End of period | shares	1,330,924
SARs, Vested, End of Period | shares	543,018
SARs, Exercisable, End of Period | shares	543,018
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Weighted Average Exercise Price [Roll Forward]
Weighted Average Exercise Prices, Outstanding, Beginning of Period | $ / shares	$ 27.12
Weighted Average Exercise Prices, Granted | $ / shares	14.67
Weighted Average Exercise Prices, Exercised | $ / shares	0.00
Weighted Average Exercise Prices, Forfeitures | $ / shares	0.00
Weighted Average Exercise Prices, Expired | $ / shares	0.00
Weighted Average Exercise Prices, Outstanding, End of Period | $ / shares	21.35
Weighted Average Exercise Prices, Vested, End of Period | $ / shares	27.18
Weighted Average Exercise Prices, Exercisable, End of Period | $ / shares	$ 27.18
Cash paid at exercises, Stock Appreciation Rights | $	$ 0.0
Weighted Average Remaining Life, Outstanding, End of Period	4 years 9 months 29 days
Weighted Average Remaining Life, Exercisable, End of Period	3 years 14 days
Aggregate Intrinsic Value, Outstanding, End of Period | $	$ 9.1
Aggregate Intrinsic Value, Exercisable, End of Period | $	$ 0.5