MBS Investments Terms of MBS (Details) (Trust Portfolio--MBS Bonds [Member], USD $)	3 Months Ended	12 Months Ended
	Mar. 31, 2013	Dec. 31, 2013	Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]
Available for Sale Securities, not Including Premiums		$ 42,830,000	$ 31,620,000
Debt, Weighted Average Interest Rate		1.30%	1.30%
Standard & Poor's, AAA Rating [Member]
Schedule of Available-for-sale Securities [Line Items]
Debt Instrument, Credit Rating	"AAA"	"AAA"	"AAA"
Available for Sale Securities, not Including Premiums		22,710,000	12,675,000
Debt Instrument, Maturity Date	Dec. 09, 2037
Debt, Weighted Average Interest Rate	4.05%
Standard & Poor's, AA Rating [Member]
Schedule of Available-for-sale Securities [Line Items]
Debt Instrument, Credit Rating	"AA"	"AA"	"AA"
Available for Sale Securities, not Including Premiums		$ 20,120,000	$ 18,945,000
Debt Instrument, Maturity Date	Feb. 05, 2037
Debt, Weighted Average Interest Rate	4.00%