Stock Compensation Plans (Details Textual) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended								1 Months Ended			12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 1998 Long-Term Incentive Plan [Member]	Dec. 31, 2012 2006 Long-Term Incentive Plan [Member]	Dec. 31, 2009 2006 Long-Term Incentive Plan [Member]	Dec. 31, 2012 Prior To 2009 Long Term Incentive Plans [Member]	Dec. 31, 2012 2009 Long Term Incentive Plan [Member]	Feb. 28, 2013 2010 Long-Term Incentive Plan [Member]	Feb. 28, 2012 2010 Long-Term Incentive Plan [Member]	Feb. 28, 2011 2010 Long-Term Incentive Plan [Member]	Dec. 31, 2012 2010 Long-Term Incentive Plan [Member]
Stock Compensation Plans (Textual) [Abstract]
Number of shares reserved (in shares)				3,900,000	1,500,000							2,000,000
Period of vesting of awards				3 years	3 years
Period of life of awards granted				6 years	10 years		6 years	10 years				10 years
Percentage of shares vested initially (in hundredths)				40.00%
Period between former and latter vesting of options				2 years
Percentage of shares vested after two years (in hundredths)				20.00%
Vesting of exercisable options				10 years
Vesting of granted awards					3 years						3 years	3 years
Restricted stock awards, granted (in shares)						40,000					75,000
Share-based Compensation Expense	$ 4.5	$ 3.2	$ 4.1
Restricted stock expense	0	1.7	0.5
Unrecognized stock compensation expense	$ 3.0
Expected weighted average period of recognition	1 year 4 months 24 days
Restricted stock awards fair value, granted (in dollars per share)						$ 28.42					$ 30.66
Percentage of shares vested (in hundredths)									33.33%	33.33%