Share-Based Compensation Plans (Schedule of Option Activity) (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding at the beginning of year (in shares)	343,742
Granted (in shares)	0	0	0
Exercised (in shares)	(29,940)
Forfeited or expired (in shares)	0
Outstanding at the end of year (in shares)	313,802	343,742
Exercisable at the end of year (in shares)	313,802
Outstanding at the beginning of year, Weighted-Average Exercise Price (in dollars per share)	$ 61.55
Granted, Weighted-Average Exercise Price (in dollars per share)	0.00
Exercised, Weighted-Average Exercise Price (in dollars per share)	68.04
Forfeited or Expired, Weighted-Average Exercise Price (in dollars per share)	0.00
Outstanding at the end of year, Weighted-Average Exercise Price (in dollars per share)	60.93	$ 61.55
Exercisable at the end of the year, Weighted-Average Exercise Price (in dollars per share)	$ 60.93
Outstanding at the end of year, Weighted-Average Remaining Contractual Term (in years)	2 years 6 months
Exercisable at the end of year, Weighted-Average Remaining Contractual Term (in years)	2 years 6 months
Outstanding at the end of year, Aggregate Intrinsic Value	$ 26,726
Exercisable at the end of year, Aggregate Intrinsic Value	$ 26,726