Accounting for Stock-Based Compensation (Schedule of Share-based Compensation, Stock Options, Activity) (Details) - Employee Stock Option [Member] - $ / shares	3 Months Ended			9 Months Ended
	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Sep. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Beginning Balance, shares	1,152,337	1,168,505	1,185,320	1,185,320
Forfeited and Cancelled, Shares	(20,168)	(16,168)	(16,815)
Ending Balance, shares	1,132,169	1,152,337	1,168,505	1,132,169
Beginning of Period, Weighted Average Exercise Price	$ 31.65	$ 31.71	$ 28.12	$ 28.12
Forfeited and Cancelled, Weighted Average Exercise Price	35.73	36.59	28.82
End of Period, Weighted Average Exercise Price	$ 31.56	$ 31.65	$ 31.71	$ 31.56
Weighted Average Remaining Contractual Term				2 years 2 months 12 days
Exercisable, Shares	1,132,169			1,132,169
Exercisable, Weighted Average Exercise Price	$ 31.56			$ 31.56
Exercisable, Weighted Average Remaining Contractual Term				2 years 2 months 12 days