XML 79 R59.htm IDEA: XBRL DOCUMENT

Summary of Significant Accounting Policies - Concentration of Credit Risk (Details) (Consolidated Gross Revenues [Member])	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Consolidated Gross Revenues [Member]
Concentration Risk, Customer	0	0	0
Concentration Risk, Percentage	10.00%

Description of risks that arise due to the volume of business transacted with a particular customer. At a minimum, the description informs financial statement users of the general nature of the risk, but excludes "Information about Major Customers" that may be disclosed elsewhere (for instance, segment disclosures).

+ References+ Details