Stock-Based Compensation Plans (Details) - Jun. 30, 2015 - Employee Stock Option [Member] - USD ($)		Total
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares, Outstanding at December 31, 2014		1,355,416
Shares, Exercised		(130,491)
Shares, Forfeited or expired		(10,000)
Shares, Outstanding at June 30, 2015		1,214,925
Shares, Exercisable at June 30, 2015		472,018
Weighted Average Exercise Price, Outstanding at December 31, 2014		$ 25.36
Weighted Average Exercise Price, Exercised		19.26
Weighted Average Exercise Price, Forfeited or expired		26.72
Weighted Average Exercise Price, Outstanding at June 30, 2015		26.01
Weighted Average Exercise Price, Exercisable at June 30, 2015		$ 24.86
Weighted Average Remaining Contractual Term (Years), Outstanding - June 30, 2015		3 years 8 months 12 days
Weighted Average Remaining Contractual Term (Years), Exercisable - June 30, 2015		2 years 4 months 24 days
Aggregate Intrinsic Value, Outstanding at June 30, 2015	[1]	$ 4,633,000
Aggregate Intrinsic Value, Exercisable at June 30, 2015	[1]	$ 2,339,000

[1] The aggregate intrinsic value of outstanding and exercisable stock options is defined as the difference between the closing price of the Company's stock on June 30, 2015, the last trading day of the quarter, of $29.82 and the exercise price multiplied by the number of in-the-money outstanding and exercisable stock options.