Long-term Equity-based Compensation Plans Schedule of Nonvested Restricted Stock Units Activity (Details) (USD $) In Millions, except Share data, unless otherwise specified	9 Months Ended											0 Months Ended	36 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014 Time Vested Restricted Stock [Member]	Sep. 30, 2014 Performance Based Restricted Stock [Member]	Sep. 30, 2014 Performance Based Restricted Stock Units [Member]	Sep. 30, 2014 Restricted Stock [Member]	Sep. 30, 2013 Restricted Stock [Member]	Sep. 30, 2014 Time Vested Restricted Stock Units [Member]	Sep. 30, 2014 Performance Period, 2014 to 2016 [Member] Performance Based Restricted Stock [Member]	Sep. 30, 2014 Performance Period, 2013 to 2015 [Member] Performance Based Restricted Stock [Member]	Sep. 30, 2014 Performance Period, 2012 to 2014 [Member] Performance Based Restricted Stock [Member]	Feb. 01, 2014 Performance Period, 2011 to 2013 [Member] Performance Based Restricted Stock [Member]	Dec. 31, 2013 Performance Period, 2011 to 2013 [Member] Performance Based Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Proceeds from Stock Options Exercised	$ 0	$ 0.6
Restricted Stock, Nonvested at Beginning of Year, Number			101,627	176,800	0			0
Restricted Stock, Nonvested at Beginning of Year, Weighted Average Grant Date Fair Value			$ 31.48	$ 39.54	$ 0.00			$ 0.00
Restricted Stock, Grants in Period			2,000	0	66,575			41,925
Restricted Stock, Weighted Average Grant Date Fair Value			$ 38.59	$ 0.00	$ 40.50			$ 36.56
Restricted Stock, Vested in Period			(25,568)	(54,934)	0			(9,351)
Restricted Stock, Vested in Period, Weighted Average Grant Date Fair Value			$ 30.56	$ 39.83	$ 0.00			$ 36.47
Restricted Stock, Forfeited in Period			(21,789)	(7,691)	(1,400)			(1,500)
Restricted Stock, Forfeitures, Weighted Average Grant Date Fair Value			$ 31.00	$ 40.12	$ 40.50			$ 36.47
Restricted Stock, Nonvested at End of Period, Number			56,270	114,175	65,175			31,074
Restricted Stock, Nonvested at End of Period, Weighted Average Grant Date Fair Value			$ 32.33	$ 39.37	$ 40.50			$ 36.60
Number of Additional Shares To Be Granted If Maximum Perfornance Level Is Met or Exceeded									65,175	56,400	57,775
Payout Percentage for Exceeding Performance Target													118.00%
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures												9,014
Restricted Stock, Vested in Period, Total Fair Value						3.6	4.0
Restricted Stock, Vested in Period, Tax Benefits						$ 1.2	$ 1.4
Performance Period				3 years