Share-Based Plans (Options Outstanding and Options Exercisable) (Details)	12 Months Ended
	Dec. 31, 2017 $ / shares shares
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Number of Shares | shares	673,039
Options Outstanding, Weighted-Average Remaining Contractual Life (years)	3 years 4 months 24 days
Options Outstanding, Weighted-Average Exercise Price (in dollars per share)	$ 18.75
Options Exercisable, Number of Shares | shares	673,039
Options Exercisable, Weighted-Average Remaining Contractual Life (years)	3 years 4 months 15 days
Options Exercisable, Weighted-Average Remaining Contractual Life (years)	$ 18.75
$5.14 - 12.85 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of exercise prices, Minimum (in dollars per share)	5.14
Range of exercise prices, Maximum (in dollars per share)	$ 12.85
Options Outstanding, Number of Shares | shares	222,947
Options Outstanding, Weighted-Average Remaining Contractual Life (years)	1 year 2 months 12 days
Options Outstanding, Weighted-Average Exercise Price (in dollars per share)	$ 9.43
Options Exercisable, Number of Shares | shares	222,947
Options Exercisable, Weighted-Average Remaining Contractual Life (years)	1 year 2 months
Options Exercisable, Weighted-Average Remaining Contractual Life (years)	$ 9.43
22.04 - 25.15 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of exercise prices, Minimum (in dollars per share)	22.04
Range of exercise prices, Maximum (in dollars per share)	$ 25.15
Options Outstanding, Number of Shares | shares	450,092
Options Outstanding, Weighted-Average Remaining Contractual Life (years)	4 years 6 months
Options Outstanding, Weighted-Average Exercise Price (in dollars per share)	$ 23.37
Options Exercisable, Number of Shares | shares	450,092
Options Exercisable, Weighted-Average Remaining Contractual Life (years)	4 years 6 months 2 days
Options Exercisable, Weighted-Average Remaining Contractual Life (years)	$ 23.37