Share-Based Arrangements Stock Options Activity (Details) (Stock Options [Member], USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding at beginning of period	891,932
Granted	186,885
Exercised	(163,245)
Forfeited or expired	(11,481)
Outstanding at end of period	904,091	891,932
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Options outstanding at beginning of period, Weighted average-exercise price	$ 31.26	$ 28.18
Granted, Weighted Average Grant Date Fair Value	$ 39.22
Exercised, Weighted average-exercise price	$ 23.21
Forfeited or expired, Weighted average exercise price	$ 35.68
Options outstanding at end of period, Weighted average-exercise price	$ 31.26	$ 28.18
Weighted-average remaining contractual term - options outstanding	6 years 2 months
Aggregate intrinsic value - options outstanding	$ 8,180,000
Options exercisable	415,955
Weighted-average remaining contractual term - options exercisable	4 years 6 months
Aggregate intrinsic value - options exercisable	5,816,000
Weighted-average exercise price - options exercisable	$ 26.33
Intrinsic Value	$ 2,900,000	$ 1,900,000	$ 3,200,000
Expected option term	5 years 1 month	5 years 2 months 5 days	5 years 5 months 5 days
Expected volatility	37.50%	45.50%	46.50%
Risk-free interest rate	1.50%	0.90%	0.90%
Expected dividend yield	1.70%	2.00%	1.90%
Per share fair value of options granted	$ 11.60	$ 12.38	$ 12.00