Share-based Compensation (Option Price Ranges) (Details) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Stock options outstanding	162,000
Stock options outstanding, Weighted Average Remaining Contractual Term (in years)	3 years 20 days	2 years 11 months 8 days	3 years 3 months 12 days	2 years 3 months 25 days
Stock options outstanding, Weighted Average Exercise Price (in dollars per share)	$ 42.75	$ 37.68	$ 30.73	$ 15.17
Stock options exercisable	80,250
Stock options exercisable, Weighted Average Exercise Price (in dollars per share)	$ 38.21
$21.19 Exercise Price Range
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Shares authorized under stock option plans, exercise price range, lower range limit	21.19
Shares authorized under stock option plans, exercise price range, upper range limit	$ 21.19
Stock options outstanding, by exercise price range	30,000
Stock options outstanding, Weighted Average Remaining Contractual Term (in years)	2 months 10 days
Stock options outstanding, Weighted Average Exercise Price, by exercise price range (in dollars per share)	$ 3.93
Stock options exercisable, by exercise price range	30,000
Stock options exercisable, Weighted Average Exercise Price, by exercise price range (in dollars per share)	$ 7.92
$28.59 Exercise Price Range
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Shares authorized under stock option plans, exercise price range, lower range limit	28.59
Shares authorized under stock option plans, exercise price range, upper range limit	$ 28.59
Stock options outstanding, by exercise price range	6,000
Stock options outstanding, Weighted Average Remaining Contractual Term (in years)	20 days
Stock options outstanding, Weighted Average Exercise Price, by exercise price range (in dollars per share)	$ 1.06
Stock options exercisable, by exercise price range	5,625
Stock options exercisable, Weighted Average Exercise Price, by exercise price range (in dollars per share)	$ 2.00
$42.56 Exercise Price Range
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Shares authorized under stock option plans, exercise price range, lower range limit	42.56
Shares authorized under stock option plans, exercise price range, upper range limit	$ 42.56
Stock options outstanding, by exercise price range	42,000
Stock options outstanding, Weighted Average Remaining Contractual Term (in years)	1 year 3 months 20 days
Stock options outstanding, Weighted Average Exercise Price, by exercise price range (in dollars per share)	$ 11.03
Stock options exercisable, by exercise price range	0
Stock options exercisable, Weighted Average Exercise Price, by exercise price range (in dollars per share)	$ 0.00
$49.22 Exercise Price Range
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Shares authorized under stock option plans, exercise price range, lower range limit	49.22
Shares authorized under stock option plans, exercise price range, upper range limit	$ 49.22
Stock options outstanding, by exercise price range	42,000
Stock options outstanding, Weighted Average Remaining Contractual Term (in years)	7 months 8 days
Stock options outstanding, Weighted Average Exercise Price, by exercise price range (in dollars per share)	$ 12.76
Stock options exercisable, by exercise price range	28,875
Stock options exercisable, Weighted Average Exercise Price, by exercise price range (in dollars per share)	$ 17.71
$53.90 Exercise Price Range
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Shares authorized under stock option plans, exercise price range, lower range limit	53.90
Shares authorized under stock option plans, exercise price range, upper range limit	$ 53.90
Stock options outstanding, by exercise price range	42,000
Stock options outstanding, Weighted Average Remaining Contractual Term (in years)	10 months 29 days
Stock options outstanding, Weighted Average Exercise Price, by exercise price range (in dollars per share)	$ 13.97
Stock options exercisable, by exercise price range	15,750
Stock options exercisable, Weighted Average Exercise Price, by exercise price range (in dollars per share)	$ 10.58