Share-Based Compensation Plans (Schedule of Option Activity) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding at the beginning of year (in shares)	375,460
Granted (in shares)	0	0	0
Exercised (in shares)	(29,218)
Forfeited or expired (in shares)	(2,500)
Outstanding at the end of year (in shares)	343,742	375,460
Exercisable at the end of year (in shares)	343,599
Outstanding at the beginning of year, Weighted-Average Exercise Price (in dollars per share)	$ 63.00
Granted, Weighted-Average Exercise Price (in dollars per share)	$ 0.00
Exercised, Weighted-Average Exercise Price (in dollars per share)	$ 73.38
Forfeited or Expired, Weighted-Average Exercise Price (in dollars per share)	$ 82.15
Outstanding at the end of year, Weighted-Average Exercise Price (in dollars per share)	$ 61.55	$ 63.00
Exercisable at the end of the year, Weighted-Average Exercise Price (in dollars per share)	$ 61.55
Outstanding at the end of year, Weighted-Average Remaining Contractual Term (in years)	3 years 5 months
Exercisable at the end of year, Weighted-Average Remaining Contractual Term (in years)	3 years 5 months
Outstanding at the end of year, Aggregate Intrinsic Value	$ 24,719
Exercisable at the end of year, Aggregate Intrinsic Value	$ 24,709