Stock-Based Compensation Plans (Details) (Employee Stock Option [Member], USD $)	9 Months Ended
	Sep. 30, 2014
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares, Outstanding at December 31, 2013	1,260,866
Shares, Granted	331,600
Shares, Exercised	(59,100)
Shares, Forfeited or expired	(11,800)
Shares, Outstanding at September 30, 2014	1,521,566
Shares, Exercisable at September 30, 2014	519,981
Weighted Average Exercise Price, Outstanding at December 31, 2013	$ 24.41
Weighted Average Exercise Price, Granted	$ 27.04
Weighted Average Exercise Price, Exercised	$ 20.74
Weighted Average Exercise Price, Forfeited or expired	$ 25.49
Weighted Average Exercise Price, Outstanding at September 30, 2014	$ 25.11
Weighted Average Exercise Price, Exercisable at September 30, 2014	$ 22.57
Weighted Average Remaining Contractual Term (Years), Outstanding at September 30, 2014	3 years 8 months 12 days
Weighted Average Remaining Contractual Term (Years), Exercisable at September 30, 2014	1 year 6 months
Aggregate Intrinsic Value, Outstanding at September 30, 2014	$ 1,742,000	[1]
Aggregate Intrinsic Value, Exercisable at September 30, 2014	$ 1,321,000	[1]

[1] The aggregate intrinsic value of outstanding and exercisable stock options is defined as the difference between the market value of the Company's stock on September 30, 2014, the last trading day of the quarter, of $25.11 and the exercise price multiplied by the number of in-the-money outstanding and exercisable stock options.