Goodwill (Schedule Of Goodwill) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Goodwill [Line Items]
Goodwill, Beginning Balance	$ 114,963	$ 113,701	$ 46,832
Consideration paid related to prior business acquisitions	829	1,262	4,767
Goodwill, Ending Balance	596,103	114,963	113,701
Parent/Issuer [Member]
Goodwill [Line Items]
Consideration paid related to prior business acquisitions	829	1,262	4,767
Jacobs Ranch [Member]
Goodwill [Line Items]
Acquisition during period			62,102
ICG [Member]
Goodwill [Line Items]
Acquisition during period	$ 480,311