Stock-Based Awards and Programs (Details 2) (Stock Options, USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Stock options
Outstanding, balance at the beginning of the period (in shares)	163,300	190,300
Granted (in shares)	0
Exercised (in shares)	34,800	27,000
Outstanding, balance at the end of the period (in shares)	128,500	163,300
Exercisable (in shares)	128,500	128,500
Weighted Average Exercise Price
Outstanding, balance at the beginning of the period (in dollars per option)	$ 23.15	$ 21.56
Granted (in dollars per share)	$ 0.00
Exercised (in dollars per share)	$ 18.36	$ 18.12
Outstanding, balance at the end of the period (in dollars per option)	$ 23.15	$ 22.13
Exercisable (in dollars per share)	$ 23.15	$ 23.15
Intrinsic value of unexercised options if closing price of stock is less than the exercise price (in dollars per share)	$ 0
Aggregate intrinsic value
Weighted-average remaining contractual life of outstanding options	2 years 9 months 18 days	3 years 10 months 24 days
Range of exercise prices, low end of range (in dollars per share)	$ 21.79	$ 18.36
Range of exercise prices, high end of range (in dollars per share)	$ 23.81	$ 23.81
Maximum
Aggregate intrinsic value
Aggregate intrinsic value of unexercised options	$ 0.1	$ 0.1
Total unrecognized compensation expense related to non-vested options and related dividend equivalents granted under the plan	$ 0	$ 0.1
Recognition period		1 year