Fair Value Measurements (Narrative) (Details) (USD $)	1 Months Ended	6 Months Ended		3 Months Ended	6 Months Ended
	May 31, 2011	Jun. 30, 2011 A years months	Dec. 31, 2010	Jun. 30, 2011 Disposed Properties[Member] A	Jun. 30, 2011 Qualifying Special Purpose [Member]	Jun. 30, 2010 Qualifying Special Purpose [Member]
Interest income					$ 300,000	$ 300,000
Term on alliance agreement (years)		3
Break-even payments to Southwest in the second year		12,000,000
Standby guarantee liability		800,000	800,000
Payments received from collar agreement	400,000
Valuation adjustments and write-offs		2,500,000
Number of real estate properties				4
Long-lived assets held for sale		4,600,000
Land owned		574,000		53
Fair value of long-lived assets		2,925,000
Impairment loss on long lived assets		1,697,000
Impaired predevelopment costs		$ 800,000