Marketing Expenses (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Marketing Expenses [Abstract]
Marketing expense	$ 72.2	$ 41.2	$ 30.1
Lead purchase expense	$ 49.7	$ 43.2	$ 40.5

Expenditures for planning and executing the conception, pricing, promotion, and distribution of ideas, goods, and services. Costs of public relations and corporate promotions are typically considered to be marketing costs.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.4)

-URI http://asc.fasb.org/extlink&oid=6880815&loc=d3e20235-122688

Name:	us-gaap_MarketingExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration