Fair Value Measurements (Summary Of Book Value And Fair Value Of Current And Long-Term Portion Of Loans Payable) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012		Dec. 31, 2011
Fair Value Measurements [Abstract]
Current portion of loans payable, Book Value	$ 71,614		$ 91,597
Long-term portion of loans payable, Book Value	32,528		32,133
Total loans payable, Book Value	104,142
Current portion of loans payable, Fair Value	71,614	[1]
Long-term portion of loans payable, Fair Value	32,528	[1]
Total loans payable, Fair Value	$ 104,142	[1]

[1] Estimated fair value of long-term debt is measured using the income approach. This fair value measurement is based on similar grade US Treasury security re-priced at March 31, 2012 plus contractual spread and thus represents Level 2 inputs under the fair value hierarchy.