Stock Based-Compensation (Details 5) (USD $)	12 Months Ended
	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Balance at January 1, 2012	726,224
Grants	167,320
Forfeitures	(37,767)
Vested and Issued	(258,129)
Balance at December 31, 2012	597,648
Weighted Average Grant Date Fair Value Per Share - Balance at January 1, 2012	$ 42.25
Weighted Average Grant Date Fair Value Per Share - Grants	$ 53.71
Weighted Average Grant Date Fair Value Per Share - Foreitures	$ 48.46
Weighted Average Grant Date Fair Value Per Share - Vested and issued	$ 34.41
Weighted Average Grant Date Fair Value Per Share - Balance at December 31, 2012	$ 48.33