Stock Based Compensation Schedule of Share-based Compensation, Shares Authorized under Stock Option Plans, by Exercise Price Range (Details) (USD $)	12 Months Ended
	Dec. 31, 2014
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of Shares Outstanding, Outstanding Options, in shares	401,442
Weighted-Average Remaining Contractual Life, Outstanding Options, in years	5 years 9 months 28 days
Weighted Average Exercise Price, Outstanding Options, in Weighted Average Exercise Price	$ 22.55
Number of Shares Outstanding, Exercisable Options, in shares	266,654
Weighted-Average Remaining Contractual Life, Exercisable Options, in years	4 years 8 months 3 days
Weighted-Average Exercise Price, Exercisable Options, in Weighted Average Exercise Price	$ 21.74
Exercise Price Range $18.71 to $19.48 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of Shares Outstanding, Outstanding Options, in shares	72,516
Weighted-Average Remaining Contractual Life, Outstanding Options, in years	3 years 8 months 10 days
Weighted Average Exercise Price, Outstanding Options, in Weighted Average Exercise Price	$ 19.24
Number of Shares Outstanding, Exercisable Options, in shares	72,516
Weighted-Average Remaining Contractual Life, Exercisable Options, in years	3 years 8 months 10 days
Weighted-Average Exercise Price, Exercisable Options, in Weighted Average Exercise Price	$ 19.24
Exercise Price Range $20.82 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of Shares Outstanding, Outstanding Options, in shares	27,470
Weighted-Average Remaining Contractual Life, Outstanding Options, in years	1 year 11 months 2 days
Weighted Average Exercise Price, Outstanding Options, in Weighted Average Exercise Price	$ 20.82
Number of Shares Outstanding, Exercisable Options, in shares	27,470
Weighted-Average Remaining Contractual Life, Exercisable Options, in years	1 year 11 months 2 days
Weighted-Average Exercise Price, Exercisable Options, in Weighted Average Exercise Price	$ 20.82
Exercise Price Range $21.83 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of Shares Outstanding, Outstanding Options, in shares	64,829
Weighted-Average Remaining Contractual Life, Outstanding Options, in years	5 years 0 months 28 days
Weighted Average Exercise Price, Outstanding Options, in Weighted Average Exercise Price	$ 21.83
Number of Shares Outstanding, Exercisable Options, in shares	64,829
Weighted-Average Remaining Contractual Life, Exercisable Options, in years	5 years 0 months 28 days
Weighted-Average Exercise Price, Exercisable Options, in Weighted Average Exercise Price	$ 21.83
Exercise Price Range $23.30 to $23.95 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of Shares Outstanding, Outstanding Options, in shares	153,236
Weighted-Average Remaining Contractual Life, Outstanding Options, in years	6 years 7 months 27 days
Weighted Average Exercise Price, Outstanding Options, in Weighted Average Exercise Price	$ 23.61
Number of Shares Outstanding, Exercisable Options, in shares	92,333
Weighted-Average Remaining Contractual Life, Exercisable Options, in years	6 years 5 months 10 days
Weighted-Average Exercise Price, Exercisable Options, in Weighted Average Exercise Price	$ 23.56
Exercise Price Range $24.51 to $25.27 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of Shares Outstanding, Outstanding Options, in shares	83,391
Weighted-Average Remaining Contractual Life, Outstanding Options, in years	8 years 0 months 18 days
Weighted Average Exercise Price, Outstanding Options, in Weighted Average Exercise Price	$ 24.60
Number of Shares Outstanding, Exercisable Options, in shares	9,506
Weighted-Average Remaining Contractual Life, Exercisable Options, in years	8 years 0 months 18 days
Weighted-Average Exercise Price, Exercisable Options, in Weighted Average Exercise Price	$ 25.27