Significant Acquisitions and Dispositions Significant Acquisitions and Dispositions (Calculation of Gain (Loss) on Acquisition) (Details) (Dugan Realty [Member], USD $) In Thousands, unless otherwise specified	0 Months Ended
	Jul. 01, 2010
Dugan Realty [Member]
Significant Acquisitions and Disposals [Line Items]
Business Combination, Step Acquisition, Equity Interest in Acquiree, Percentage	50.00%
Business Combination, Step Acquisition, Equity Interest in Acquiree, Fair Value	$ 166,306
Equity Method Investments	158,591
Business Acquisition, Put Option Liability Derecognized	(50,000)
Equity Method Investments, Net of Liabilities Derecognized	108,591
Business Combination, Step Acquisition, Equity Interest in Acquiree, Remeasurement Gain (Loss), Net	$ 57,715