Share-Based Payments (General Descriptions) (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended						9 Months Ended						9 Months Ended
	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012 Common Class A [Member]	Dec. 31, 2011 Common Class A [Member]	Jun. 20, 2008 Common Class A [Member]	Jun. 25, 2004 Common Class A [Member]	Sep. 30, 2012 Director [Member]	Sep. 30, 2012 Employees [Member]	Jun. 25, 2004 1995 Plan [Member]	Jun. 20, 2008 2008 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, par value									$ 1	$ 1	$ 1	$ 1
Share-based payments, number of shares authorized under plans															300,000	300,000
Annual vesting percentage													20.00%	20.00%
Requisite service period of awards													1 year	3 years
Expiration period of awards							10 years
Awards issued during the period (in shares)	0	0	0	0	0	0
Period in force, from which option holders may elect to sell back acquired shares							90 days
Pre-tax compensation cost (benefit) recognized							$ 0.4	$ (2.2)
Compensation cost (benefit), tax expense (benefit)							0.1	(0.8)
Compensation cost related to nonvested options not yet recognized	$ 1.6						$ 1.6
Compensation cost related to nonvested options not yet recognized, weighted-average period of recognition							3 years 6 months