Mortgage Loans on Real Estate (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Mortgage Loans on Real Estate [Line Items]
Size of loans	$ 55,387	$ 39,524	$ 69,701
Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Number of loans	148
Carrying Amount of Mortgages	174,136
Principal amount of loan subject to delinquent principal or "interest"	3,203
Texas [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Number of loans	24
Carrying Amount of Mortgages	25,246
Final maturity date Start	Jan. 21, 2015
Final Maturity Date End	Aug. 16, 2031
Principal amount of loan subject to delinquent principal or "interest"
Texas [Member] | Conventional Loans [Member] | Variable Interest Rate [Member]
Mortgage Loans on Real Estate [Line Items]
Mortgage loan on minimum interest rate	3.11%
Mortgage loan on maximum interest rate	7.25%
Texas [Member] | Maximum [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Size of loans	3,000
Texas [Member] | Minimum [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Size of loans	0
Texas One [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Number of loans	14
Carrying Amount of Mortgages	7,441
Final maturity date Start	Nov. 15, 2013
Final Maturity Date End	Nov. 18, 2030
Principal amount of loan subject to delinquent principal or "interest"
Texas One [Member] | Conventional Loans [Member] | Fixed Interest Rate [Member]
Mortgage Loans on Real Estate [Line Items]
Mortgage loan on minimum interest rate	8.00%
Mortgage loan on maximum interest rate	10.78%
Texas One [Member] | Maximum [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Size of loans	2,000
Texas One [Member] | Minimum [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Size of loans	0
Virginia [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Number of loans	7
Carrying Amount of Mortgages	17,500
Final maturity date Start	Jan. 30, 2023
Final Maturity Date End	Dec. 17, 2032
Principal amount of loan subject to delinquent principal or "interest"
Virginia [Member] | Conventional Loans [Member] | Variable Interest Rate [Member]
Mortgage Loans on Real Estate [Line Items]
Mortgage loan on minimum interest rate	3.36%
Mortgage loan on maximum interest rate	7.50%
Virginia [Member] | Maximum [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Size of loans	6,000
Virginia [Member] | Minimum [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Size of loans	0
Virginia One [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Number of loans	2
Carrying Amount of Mortgages	1,764
Final maturity date Start	Jun. 01, 2017
Final Maturity Date End	Aug. 21, 2027
Principal amount of loan subject to delinquent principal or "interest"
Virginia One [Member] | Conventional Loans [Member] | Fixed Interest Rate [Member]
Mortgage Loans on Real Estate [Line Items]
Mortgage loan on minimum interest rate	7.50%
Mortgage loan on maximum interest rate	8.50%
Virginia One [Member] | Maximum [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Size of loans	1,000
Virginia One [Member] | Minimum [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Size of loans	0
Arizona [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Number of loans	6
Carrying Amount of Mortgages	11,353
Final maturity date Start	Feb. 10, 2023
Final Maturity Date End	Sep. 14, 2031
Principal amount of loan subject to delinquent principal or "interest"
Arizona [Member] | Conventional Loans [Member] | Variable Interest Rate [Member]
Mortgage Loans on Real Estate [Line Items]
Mortgage loan on minimum interest rate	3.36%
Mortgage loan on maximum interest rate	7.50%
Arizona [Member] | Maximum [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Size of loans	5,000
Arizona [Member] | Minimum [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Size of loans	0
Arizona One [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Number of loans	6
Carrying Amount of Mortgages	6,317
Final maturity date Start	Jul. 16, 2013
Final Maturity Date End	Mar. 28, 2032
Principal amount of loan subject to delinquent principal or "interest"
Arizona One [Member] | Conventional Loans [Member] | Fixed Interest Rate [Member]
Mortgage Loans on Real Estate [Line Items]
Mortgage loan on minimum interest rate	7.50%
Mortgage loan on maximum interest rate	10.00%
Arizona One [Member] | Maximum [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Size of loans	3,000
Arizona One [Member] | Minimum [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Size of loans	0
Ohio [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Number of loans	6
Carrying Amount of Mortgages	11,278
Final maturity date Start	Oct. 27, 2025
Final Maturity Date End	Apr. 21, 2028
Principal amount of loan subject to delinquent principal or "interest"
Ohio [Member] | Conventional Loans [Member] | Variable Interest Rate [Member]
Mortgage Loans on Real Estate [Line Items]
Mortgage loan on minimum interest rate	3.36%
Mortgage loan on maximum interest rate	4.36%
Ohio [Member] | Maximum [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Size of loans	3,000
Ohio [Member] | Minimum [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Size of loans	0
North Carolina [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Number of loans	4
Carrying Amount of Mortgages	3,892
Final maturity date Start	Jun. 11, 2021
Final Maturity Date End	May 05, 2023
Principal amount of loan subject to delinquent principal or "interest"
North Carolina [Member] | Conventional Loans [Member] | Variable Interest Rate [Member]
Mortgage Loans on Real Estate [Line Items]
Mortgage loan on minimum interest rate	3.86%
Mortgage loan on maximum interest rate	4.86%
North Carolina [Member] | Maximum [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Size of loans	2,000
North Carolina [Member] | Minimum [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Size of loans	0
North Carolina One [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Number of loans	4
Carrying Amount of Mortgages	5,218
Final maturity date Start	Dec. 20, 2016
Final Maturity Date End	May 22, 2032
Principal amount of loan subject to delinquent principal or "interest"
North Carolina One [Member] | Conventional Loans [Member] | Fixed Interest Rate [Member]
Mortgage Loans on Real Estate [Line Items]
Mortgage loan on minimum interest rate	7.50%
Mortgage loan on maximum interest rate	9.85%
North Carolina One [Member] | Maximum [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Size of loans	3,000
North Carolina One [Member] | Minimum [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Size of loans	0
Alabama [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Number of loans	4
Carrying Amount of Mortgages	6,825
Final maturity date Start	Nov. 21, 2020
Final Maturity Date End	Oct. 01, 2026
Principal amount of loan subject to delinquent principal or "interest"
Alabama [Member] | Conventional Loans [Member] | Variable Interest Rate [Member]
Mortgage Loans on Real Estate [Line Items]
Mortgage loan on minimum interest rate	3.75%
Mortgage loan on maximum interest rate	4.61%
Alabama [Member] | Maximum [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Size of loans	3,000
Alabama [Member] | Minimum [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Size of loans	0
Alabama One [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Number of loans	2
Carrying Amount of Mortgages	1,034
Final maturity date Start	Jun. 15, 2018
Final Maturity Date End	Oct. 27, 2018
Principal amount of loan subject to delinquent principal or "interest"
Alabama One [Member] | Conventional Loans [Member] | Fixed Interest Rate [Member]
Mortgage Loans on Real Estate [Line Items]
Mortgage loan on minimum interest rate	9.50%
Alabama One [Member] | Maximum [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Size of loans	1,000
Alabama One [Member] | Minimum [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Size of loans	0
Florida [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Number of loans	3
Carrying Amount of Mortgages	4,227
Final maturity date Start	Nov. 01, 2025
Final Maturity Date End	Oct. 01, 2026
Principal amount of loan subject to delinquent principal or "interest"
Florida [Member] | Conventional Loans [Member] | Variable Interest Rate [Member]
Mortgage Loans on Real Estate [Line Items]
Mortgage loan on minimum interest rate	3.49%
Mortgage loan on maximum interest rate	4.11%
Florida [Member] | Maximum [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Size of loans	3,000
Florida [Member] | Minimum [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Size of loans	0
Florida One [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Number of loans	2
Carrying Amount of Mortgages	3,510
Final maturity date Start	Jan. 01, 2024
Final Maturity Date End	Feb. 05, 2033
Principal amount of loan subject to delinquent principal or "interest"
Florida One [Member] | Conventional Loans [Member] | Fixed Interest Rate [Member]
Mortgage Loans on Real Estate [Line Items]
Mortgage loan on minimum interest rate	7.50%
Mortgage loan on maximum interest rate	8.24%
Florida One [Member] | Maximum [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Size of loans	3,000
Florida One [Member] | Minimum [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Size of loans	0
Michigan [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Number of loans	6
Carrying Amount of Mortgages	7,235
Final maturity date Start	Feb. 10, 2026
Final Maturity Date End	Aug. 23, 2030
Principal amount of loan subject to delinquent principal or "interest"
Michigan [Member] | Conventional Loans [Member] | Variable Interest Rate [Member]
Mortgage Loans on Real Estate [Line Items]
Mortgage loan on minimum interest rate	3.24%
Mortgage loan on maximum interest rate	7.25%
Michigan [Member] | Maximum [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Size of loans	2,000
Michigan [Member] | Minimum [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Size of loans	0
Oregon [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Number of loans	2
Carrying Amount of Mortgages	5,204
Final maturity date Start	Sep. 08, 2025
Final Maturity Date End	May 13, 2030
Principal amount of loan subject to delinquent principal or "interest"
Oregon [Member] | Conventional Loans [Member] | Variable Interest Rate [Member]
Mortgage Loans on Real Estate [Line Items]
Mortgage loan on minimum interest rate	4.61%
Mortgage loan on maximum interest rate	7.25%
Oregon [Member] | Maximum [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Size of loans	4,000
Oregon [Member] | Minimum [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Size of loans	0
Oregon One [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Number of loans	3
Carrying Amount of Mortgages	1,775
Final maturity date Start	Feb. 02, 2018
Final Maturity Date End	Jun. 13, 2021
Principal amount of loan subject to delinquent principal or "interest"
Oregon One [Member] | Conventional Loans [Member] | Fixed Interest Rate [Member]
Mortgage Loans on Real Estate [Line Items]
Mortgage loan on minimum interest rate	9.00%
Mortgage loan on maximum interest rate	9.90%
Oregon One [Member] | Maximum [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Size of loans	1,000
Oregon One [Member] | Minimum [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Size of loans	0
Pennsylvania [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Number of loans	2
Carrying Amount of Mortgages	4,384
Final maturity date Start	Sep. 29, 2025
Final Maturity Date End	Aug. 01, 2032
Principal amount of loan subject to delinquent principal or "interest"
Pennsylvania [Member] | Conventional Loans [Member] | Variable Interest Rate [Member]
Mortgage Loans on Real Estate [Line Items]
Mortgage loan on minimum interest rate	4.36%
Mortgage loan on maximum interest rate	7.00%
Pennsylvania [Member] | Maximum [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Size of loans	4,000
Pennsylvania [Member] | Minimum [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Size of loans	0
Pennsylvania One [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Number of loans	1
Carrying Amount of Mortgages	2,270
Final maturity date Start	Jun. 22, 2020
Principal amount of loan subject to delinquent principal or "interest"
Pennsylvania One [Member] | Conventional Loans [Member] | Fixed Interest Rate [Member]
Mortgage Loans on Real Estate [Line Items]
Interest rate variable	10.25%
Pennsylvania One [Member] | Maximum [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Size of loans	3,000
Pennsylvania One [Member] | Minimum [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Size of loans	0
Indiana [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Number of loans	5
Carrying Amount of Mortgages	5,950
Final maturity date Start	Dec. 04, 2022
Final Maturity Date End	Feb. 26, 2032
Principal amount of loan subject to delinquent principal or "interest"
Indiana [Member] | Conventional Loans [Member] | Variable Interest Rate [Member]
Mortgage Loans on Real Estate [Line Items]
Mortgage loan on minimum interest rate	3.86%
Mortgage loan on maximum interest rate	8.25%
Indiana [Member] | Maximum [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Size of loans	2,000
Indiana [Member] | Minimum [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Size of loans	0
California [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Number of loans	4
Carrying Amount of Mortgages	4,384
Final maturity date Start	Mar. 21, 2022
Final Maturity Date End	Dec. 13, 2026
Principal amount of loan subject to delinquent principal or "interest"
California [Member] | Conventional Loans [Member] | Variable Interest Rate [Member]
Mortgage Loans on Real Estate [Line Items]
Mortgage loan on minimum interest rate	4.11%
Mortgage loan on maximum interest rate	4.75%
California [Member] | Maximum [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Size of loans	2,000
California [Member] | Minimum [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Size of loans	0
California One [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Number of loans	2
Carrying Amount of Mortgages	977
Final maturity date Start	Jul. 10, 2018
Final Maturity Date End	Dec. 28, 2024
Principal amount of loan subject to delinquent principal or "interest"
California One [Member] | Conventional Loans [Member] | Fixed Interest Rate [Member]
Mortgage Loans on Real Estate [Line Items]
Mortgage loan on minimum interest rate	8.90%
Mortgage loan on maximum interest rate	9.00%
California One [Member] | Maximum [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Size of loans	1,000
California One [Member] | Minimum [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Size of loans	0
Georgia [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Number of loans	3
Carrying Amount of Mortgages	2,236
Final maturity date Start	Dec. 26, 2017
Final Maturity Date End	Dec. 14, 2027
Principal amount of loan subject to delinquent principal or "interest"
Georgia [Member] | Conventional Loans [Member] | Variable Interest Rate [Member]
Mortgage Loans on Real Estate [Line Items]
Mortgage loan on minimum interest rate	3.86%
Mortgage loan on maximum interest rate	4.61%
Georgia [Member] | Maximum [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Size of loans	2,000
Georgia [Member] | Minimum [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Size of loans	0
Georgia One [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Number of loans	3
Carrying Amount of Mortgages	2,459
Final maturity date Start	Mar. 24, 2019
Final Maturity Date End	Dec. 01, 2029
Principal amount of loan subject to delinquent principal or "interest"
Georgia One [Member] | Conventional Loans [Member] | Fixed Interest Rate [Member]
Mortgage Loans on Real Estate [Line Items]
Mortgage loan on minimum interest rate	8.75%
Mortgage loan on maximum interest rate	10.25%
Georgia One [Member] | Maximum [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Size of loans	2,000
Georgia One [Member] | Minimum [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Size of loans	0
Iowa [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Number of loans	3
Carrying Amount of Mortgages	3,928
Final maturity date Start	Sep. 30, 2019
Final Maturity Date End	May 30, 2026
Principal amount of loan subject to delinquent principal or "interest"
Iowa [Member] | Conventional Loans [Member] | Variable Interest Rate [Member]
Mortgage Loans on Real Estate [Line Items]
Mortgage loan on minimum interest rate	4.36%
Mortgage loan on maximum interest rate	6.95%
Iowa [Member] | Maximum [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Size of loans	3,000
Iowa [Member] | Minimum [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Size of loans	0
Mississippi [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Number of loans	1
Carrying Amount of Mortgages	2,423
Final maturity date Start	Dec. 01, 2032
Principal amount of loan subject to delinquent principal or "interest"
Mississippi [Member] | Conventional Loans [Member] | Variable Interest Rate [Member]
Mortgage Loans on Real Estate [Line Items]
Mortgage loan on minimum interest rate	7.25%
Mississippi [Member] | Maximum [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Size of loans	3,000
Mississippi [Member] | Minimum [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Size of loans	0
Mississippi One [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Number of loans	2
Carrying Amount of Mortgages	1,103
Final maturity date Start	Jun. 12, 2018
Final Maturity Date End	Dec. 26, 2022
Principal amount of loan subject to delinquent principal or "interest"
Mississippi One [Member] | Conventional Loans [Member] | Fixed Interest Rate [Member]
Mortgage Loans on Real Estate [Line Items]
Mortgage loan on minimum interest rate	8.00%
Mortgage loan on maximum interest rate	9.50%
Mississippi One [Member] | Maximum [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Size of loans	1,000
Mississippi One [Member] | Minimum [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Size of loans	0
Other [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Number of loans	15
Carrying Amount of Mortgages	16,355
Final maturity date Start	Jun. 27, 2016
Final Maturity Date End	Nov. 24, 2027
Principal amount of loan subject to delinquent principal or "interest"	3,203
Other [Member] | Conventional Loans [Member] | Variable Interest Rate [Member]
Mortgage Loans on Real Estate [Line Items]
Mortgage loan on minimum interest rate	2.86%
Mortgage loan on maximum interest rate	7.00%
Other [Member] | Maximum [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Size of loans	2,000
Other [Member] | Minimum [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Size of loans	0
Other One [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Number of loans	12
Carrying Amount of Mortgages	7,848
Final maturity date Start	Aug. 20, 2014
Final Maturity Date End	Dec. 22, 2030
Other One [Member] | Conventional Loans [Member] | Fixed Interest Rate [Member]
Mortgage Loans on Real Estate [Line Items]
Mortgage loan on minimum interest rate	7.75%
Mortgage loan on maximum interest rate	12.00%
Other One [Member] | Maximum [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Size of loans	2,000
Other One [Member] | Minimum [Member] | Conventional Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Size of loans	$ 0