Stock Compensation (Transactions of Stock Option Plan) (Details) (Stock Options, USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Weighted-average exercise price (in dollars per share)
Options granted	$ 22.35	$ 20.34
Omnibus Incentive Plan
Number of shares (in shares)
Beginning balance	202,378	247,580	245,090
Options granted	23,958	23,258	45,100
Options exercised	(23,016)	(66,660)	(37,450)
Options forfeited	0	(1,800)	(5,160)
Ending balance	203,320	202,378	247,580
Weighted-average exercise price (in dollars per share)
Beginning balance	$ 39.27	$ 34.26	$ 30.30
Options granted	$ 54.36	$ 51.29	$ 36.15
Options exercised	$ 32.57	$ 24.91	$ 10.25
Options forfeited		$ 37.78	$ 37.19
Ending balance	$ 41.80	$ 39.27	$ 34.26
Exercisable options (in shares)	111,016	113,060	141,740
Exercisable options weighted average exercise price (in dollars per share)	$ 39.68	$ 38.18	$ 31.72
Omnibus Incentive Plan | Price range $18.33 — $36.15
Number of shares (in shares)
Ending balance	56,320
Weighted-average exercise price (in dollars per share)
Ending balance	$ 34.20
Weighted average contractual life (in years)	5 years 10 months 24 days
Exercise price range - minimum (in dollars per share)	$ 18.33
Exercise price range - maximum (in dollars per share)	$ 36.15
Omnibus Incentive Plan | Price range $36.16 — $38.41
Number of shares (in shares)
Ending balance	54,220
Weighted-average exercise price (in dollars per share)
Ending balance	$ 37.59
Weighted average contractual life (in years)	5 years 9 months 18 days
Exercise price range - minimum (in dollars per share)	$ 36.16
Exercise price range - maximum (in dollars per share)	$ 38.41
Omnibus Incentive Plan | Price range $38.42 — $54.36
Number of shares (in shares)
Ending balance	92,780
Weighted-average exercise price (in dollars per share)
Ending balance	$ 48.88
Weighted average contractual life (in years)	6 years 3 months 18 days
Exercise price range - minimum (in dollars per share)	$ 38.42
Exercise price range - maximum (in dollars per share)	$ 54.36