Stock Incentive Plans (Components Of The Restricted Stock Awards) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	Mar. 31, 2012 Y	Dec. 31, 2011	Mar. 31, 2011	Dec. 31, 2010
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested awards	1,845,678	1,846,115	1,536,856	1,309,489
Unrecognized compensation expense	$ 8,056
Intrinsic value	22,296
Weighted average remaining life (in years)	2.56
Service-Based Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested awards	489,918
Unrecognized compensation expense	2,436
Intrinsic value	5,918
Weighted average remaining life (in years)	2.38
Performance-Based Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested awards	1,355,760
Unrecognized compensation expense	5,620
Intrinsic value	$ 16,378
Weighted average remaining life (in years)	2.63