Long-term Equity-based Compensation Plans Schedule of Nonvested Restricted Stock Units Activity (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended									0 Months Ended	36 Months Ended
	Mar. 31, 2014 Time Vested Restricted Stock [Member]	Mar. 31, 2014 Performance Based Restricted Stock [Member]	Mar. 31, 2014 Performance Based Restricted Stock Units [Member]	Mar. 31, 2014 Restricted Stock [Member]	Mar. 31, 2013 Restricted Stock [Member]	Mar. 31, 2014 Time Vested Restricted Stock Units [Member]	Mar. 31, 2014 Performance Period, 2014 to 2016 [Member] Performance Based Restricted Stock [Member]	Mar. 31, 2014 Performance Period, 2013 to 2015 [Member] Performance Based Restricted Stock [Member]	Mar. 31, 2014 Performance Period, 2012 to 2014 [Member] Performance Based Restricted Stock [Member]	Feb. 02, 2013 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]
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			40,925
Restricted Stock, Weighted Average Grant Date Fair Value	$ 38.59	$ 0.00	$ 40.50			$ 36.60
Restricted Stock, Vested in Period	0	(54,934)	0			0
Restricted Stock, Vested in Period, Weighted Average Grant Date Fair Value	$ 0.00	$ 39.83	$ 0.00			$ 0.00
Restricted Stock, Forfeited in Period	(14,476)	(3,991)	(300)			(700)
Restricted Stock, Forfeitures, Weighted Average Grant Date Fair Value	$ 31.01	$ 40.73	$ 40.50			$ 36.47
Restricted Stock, Nonvested at End of Period, Number	89,151	117,875	66,275			40,225
Restricted Stock, Nonvested at End of Period, Weighted Average Grant Date Fair Value	$ 31.71	$ 39.37	$ 40.50			$ 36.61
Number of Additional Shares To Be Granted If Maximum Perfornance Level Is Met or Exceeded							66,275	58,300	59,575
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				$ 2.4	$ 2.6
Restricted Stock, Vested in Period, Tax Benefits				$ 0.8	$ 0.9
Performance Period		3 years