Ownership Interests and Cost Method Investments (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Summary of financial information under the equity method of accounting
Cash and cash equivalents and Other current assets	$ 27,896	$ 28,767
Non-current assets	70,184	69,218
Total assets	112,760	111,672
Current liabilities	49,722	47,125
Non-current liabilities and Long-term debt	4,691	10,770
Stockholders equity	34,891	34,818
Total liabilities and stockholders equity	112,760	111,672
Total carrying value	43,125	39,052
Cash and Cash Equivalents [Member]
Summary of financial information under the equity method of accounting
Cash and cash equivalents and Other current assets	14,680	13,687
Long-term Debt [Member]
Summary of financial information under the equity method of accounting
Non-current liabilities and Long-term debt	$ 23,456	$ 18,959