Marketing Expenses - Schedule of Marketing Expenses (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Marketing Expenses [Abstract]
Advertising	$ 74,999us-gaap_AdvertisingExpense	$ 74,294us-gaap_AdvertisingExpense	$ 50,776us-gaap_AdvertisingExpense
Customer procurement expense including lead purchase costs	42,843	52,418	49,381
Customer referral and revenue sharing expense	10,020	8,624	8,653
Total	$ 127,862us-gaap_MarketingExpense	$ 135,336us-gaap_MarketingExpense	$ 108,810us-gaap_MarketingExpense

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=26872669&loc=d3e20235-122688

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