Stock Compensation Plans Stock Compensation Plans (Summary of Vesting Date Fair Value of Awards) (Details 12) (Performance Based Operational Award [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Performance Based Operational Award [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting date fair value	$ 2,191	$ 10,892	$ 7,532