Summary Of Significant Accounting Policies (Schedule Of Fair Values Of The Net Assets (Liabilities)) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012
Derivative Counterparty [Line Items]
Total assets (liabilities)	$ 14,000
Comerica Bank [Member]
Derivative Counterparty [Line Items]
Total assets (liabilities)	8,100
Canadian Imperial Bank of Commerce [Member]
Derivative Counterparty [Line Items]
Total assets (liabilities)	2,900
Bank Of Montreal [Member]
Derivative Counterparty [Line Items]
Total assets (liabilities)	2,600
BBVA Compass Bank [Member]
Derivative Counterparty [Line Items]
Total assets (liabilities)	1,400
Bank Of America, N.A. [Member]
Derivative Counterparty [Line Items]
Total assets (liabilities)	$ (1,000)