Fair Value Measurements (Narrative) (Details) (USD $)	Dec. 31, 2011	Dec. 31, 2010
Fixed rate long-term debt, fair value	$ 105,302,000	$ 150,935,000
Fixed rate long-term debt, carrying value	101,188,000	148,109,000
Variable rate long-term debt	$ 357,575,000	$ 141,754,000