Stock-Based Compensation (Narrative) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	$ 1.1	$ 1.1	$ 2.6	$ 2.4
Stock awards vesting period, minimum (in years)	5
Stock awards vesting period, maximum (in years)	7
Stock Awards 2006 and Beyond [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)			4
Contractual terms of stock options granted (in years)			10
Stock Awards 2005 and prior [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)			3
Contractual terms of stock options granted (in years)			10