Long-term Equity-based Compensation Plans Schedule of Share-based Compensation, Nonemployee Director Deferred Stock Unit Award Plan, Activity (Details) - 6 months ended Jun. 30, 2015 - USD ($)	Total
Schedule of Share-based Compensation, Nonemployee Director Deferred Stock Unit Award Plan [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Deferred Stock Units, Outstanding, Number, Beginning of Year	8,000
Share-based Compensation Arrangement by Share-based Payment Award, Deferred Stock Units, Outstanding, Weighted Average Exercise Price, Beginning of Year	$ 34.52
Share-based Compensation Arrangement by Share-based Payment Award, Deferred Stock Units, Granted and Vested in Period	3,500
Share-based Compensation Arrangements by Share-based Payment Award, Deferred Stock Units, Granted and Vested in Period, Weighted Average Exercise Price	$ 38.38
Share-based Compensation Arrangements by Share-based Payment Award, Deferred Stock Units, Reduction for Shares Issued on Conversion	$ (4,500)
Share-based Compensation Arrangements by Share-based Payment Award, Deferred Stock Units, Reduction for Shares Issued on Conversion, Weighted Average Exercise Price	$ 34.94
Share-based Compensation Arrangements by Share-based Payment Award, Deferred Stock Units, Forfeited	$ 0
Share-based Compensation Arrangements by Share-based Payment Award, Deferred Stock Units, Forfeited, Weighted Average Exercise Price	$ 0.00
Share-based Compensation Arrangement by Share-based Payment Award, Deferred Stock Units, Outstanding, Number, End of Period	7,000
Share-based Compensation Arrangement by Share-based Payment Award, Deferred Stock Units, Outstanding, Weighted Average Exercise Price, End of Period	$ 36.17