Accounting Policies (Details)	12 Months Ended
	Dec. 31, 2011
Accounting Policies [Line Items]
Percentage of taxable income to be distributed	100.00%
Minimum [Member]
Accounting Policies [Line Items]
Interest owed on hedged borrowings reset to market rates (in days)	30
Maximum [Member]
Accounting Policies [Line Items]
Interest owed on hedged borrowings reset to market rates (in days)	90