Investments (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	9 Months Ended
Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Investments, All Other Investments [Abstract]
Long-term restricted investments	$ 5,718	$ 5,718		$ 3,999
Purchases of restricted and other investments	$ 1,719	$ 1,719	$ 0

The cash outflow to acquire investments (not to include restricted cash) that are pledged or subject to withdrawal restrictions.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Investing Activities

-URI http://asc.fasb.org/extlink&oid=6516133

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 13

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3213-108585

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration