Fair Value Measurements (Details) (USD $)	Jun. 30, 2011	Dec. 31, 2010
Parent Company [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities Held in Trust, Fair Value	$ 23,285,000	$ 20,891,000
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities Held in Trust, Fair Value	23,285,000	20,891,000
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notes Payable, Fair Value Disclosure	$ 2,200,000,000	$ 2,200,000,000