Share-Based Compensation and Benefit Plans (Restricted Stock Activity) (Details) (Restricted Stock [Member], USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Restricted Stock [Member]
Compensation expense for benefit plans	$ 2.2	$ 2.0	$ 1.7
Income tax benefit from compensation expense for benefit plans	0.8	0.8	0.6
Total fair value of shares vested (at vest date)	$ 3.3	$ 2.7	$ 2.6
Issuance of common stock under employee benefit plans, net of forfeitures and shares withheld to cover taxes, shares	21,200	23,700	49,900
Average grant-date fair value of shares issued during the period in compensation and benefit plans other than stock options	$ 102.63	$ 90.10	$ 56.18