Stock-Based Compensation (Schedule of Restricted Stock Units by Type) (Details) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Total restricted stock units vesting conditions granted	3,553	2,721	4,316
Restricted Stock Units Service Based [Member]
Restricted stock units vesting conditions granted	3,003	1,597	2,342
Restricted Stock Units Performance Based [Member]
Restricted stock units granted with performance based vesting	550	1,124	1,974