Debt (Details) (USD $)	12 Months Ended		12 Months Ended									1 Months Ended	12 Months Ended				1 Months Ended			12 Months Ended			1 Months Ended
	Dec. 31, 2010 [UnsecuredDebtMember]	Oct. 31, 2005 [UnsecuredDebtMember]	Dec. 31, 2012 [SeniorNotesDebtMember] [NotesIssuedToPartnerReFinanceALlcMember]	Dec. 31, 2011 [SeniorNotesDebtMember] [NotesIssuedToPartnerReFinanceALlcMember]	Dec. 31, 2010 [SeniorNotesDebtMember] [NotesIssuedToPartnerReFinanceALlcMember]	Dec. 31, 2008 [SeniorNotesDebtMember] [NotesIssuedToPartnerReFinanceALlcMember]	Dec. 31, 2012 [SeniorNotesDebtMember] [NotesIssuedToPartnerReFinanceBLlcMember]	Dec. 31, 2011 [SeniorNotesDebtMember] [NotesIssuedToPartnerReFinanceBLlcMember]	Dec. 31, 2010 [SeniorNotesDebtMember] [NotesIssuedToPartnerReFinanceBLlcMember]	Dec. 31, 2008 [SeniorNotesDebtMember] [NotesIssuedByPartnerReFinanceALlcMember]	Dec. 31, 2010 [SeniorNotesDebtMember] [NotesIssuedByPartnerReFinanceBLlcMember]	Nov. 30, 2006 [JuniorSubordinatedDebtMember] [NotesIssuedToPartnerReFinanceIiIncMember]	Dec. 31, 2012 [JuniorSubordinatedDebtMember] [NotesIssuedToPartnerReFinanceIiIncMember]	Dec. 31, 2011 [JuniorSubordinatedDebtMember] [NotesIssuedToPartnerReFinanceIiIncMember]	Dec. 31, 2010 [JuniorSubordinatedDebtMember] [NotesIssuedToPartnerReFinanceIiIncMember]	Dec. 31, 2009 [JuniorSubordinatedDebtMember] [NotesIssuedToPartnerReFinanceIiIncMember]	Nov. 30, 2006 [JuniorSubordinatedDebtMember] [NotesIssuedToPartnerReFinanceIiIncMember] [June12007December12016Member]	Nov. 30, 2006 [JuniorSubordinatedDebtMember] [NotesIssuedToPartnerReFinanceIiIncMember] [December12016December12066Member]	Nov. 30, 2006 [JuniorSubordinatedDebtMember] [NotesIssuedByPartnerReFinanceIiIncMember]	Dec. 31, 2009 [JuniorSubordinatedDebtMember] [NotesIssuedByPartnerReFinanceIiIncMember]	Dec. 31, 2012 [JuniorSubordinatedDebtMember] [NotesIssuedByPartnerReFinanceIiIncMember]	Dec. 31, 2011 [JuniorSubordinatedDebtMember] [NotesIssuedByPartnerReFinanceIiIncMember]	Nov. 30, 2006 [JuniorSubordinatedDebtMember] [NotesIssuedByPartnerReFinanceIiIncMember] [June12007December12016Member]	Nov. 30, 2006 [JuniorSubordinatedDebtMember] [NotesIssuedByPartnerReFinanceIiIncMember] [December12016December12066Member]
Debt Instruments [Line Items]
Interest expense incurred (debt-related)	$ 1,200,000		$ 17,200,000	$ 17,200,000	$ 17,200,000		$ 27,500,000	$ 27,500,000	$ 21,800,000				$ 4,600,000	$ 4,600,000	$ 4,600,000
Interest paid during period (debt - related)	1,600,000		17,200,000	17,200,000	17,200,000		27,500,000	27,500,000	19,600,000				4,600,000	4,600,000	4,600,000
Face amount of debt instrument		400,000,000				250,000,000			500,000,000	250,000,000	500,000,000	257,600,000							250,000,000
Earliest date that debt may be redeemed other than upon occurrence of specific rating agency or tax events																			2016-12-01
Stated interest rate of debt instrument						6.875%			5.50%	6.875%	5.50%						6.44%						6.44%
Interest rate in excess of LIBOR	0.85%																	2.325%						2.325%
Payment frequency						semi-annual			semi-annual	semi-annual	semi-annual						semi-annual	quarterly					semi-annual	quarterly
Date of first required interest payment						Dec. 01, 2008			Jun. 01, 2010	Dec. 01, 2008	Jun. 01, 2010	Jun. 01, 2007							Jun. 01, 2007
Carrying amount at balance sheet date													71,000,000	71,000,000							63,400,000	63,400,000
Repayments of debt during the period	200,000,000															93,300,000				93,300,000
Net realized gain on purchase of capital efficient notes																88,400,000
Amount of debt extinguished																186,600,000				186,600,000
Percentage of outstanding debt extinguished																				75.00%
Maturity date						Jun. 01, 2018			Jun. 01, 2020	Jun. 01, 2018	Jun. 01, 2020	Dec. 01, 2066							Dec. 01, 2066
Cash tender offer																				500
Face value																				$ 1,000