Reinsurance Agreements (Details) (USD $)	3 Months Ended	9 Months Ended
	Mar. 31, 2014 Structure	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2013
Reinsurance Agreements [Abstract]
Number of types of reinsurance structures	3
Liability for Catastrophe Claims [Line Items]
Prepaid reinsurance premiums	$ 837,000			$ 7,592,000
Increase in total insured value		8,700,000,000	2,100,000,000
Percentage increase in total insured value (in hundredths)		25.30%	12.50%
Increase reinsurance premiums for total insured value		8,300,000	2,400,000
Percentage increase in reinsurance premiums for total insured value (in hundredths)		13.80%	6.00%
Trust agreement for loss exposure	4,800,000			4,900,000
2012-2013 Hurricane Season [Member]
Liability for Catastrophe Claims [Line Items]
Aggregate catastrophic loss coverage	328,300,000
Maximum single event coverage	246,500,000
Amount retained per Loss	8,000,000
Coverage afforded by FHCF	144,700,000
Percentage of FHCF coverage to total coverage (in hundredths)	44.10%
Reinsurance premium	11,200,000
Prepaid reinsurance premiums	43,100,000
2013-2014 Hurricane Season [Member]
Liability for Catastrophe Claims [Line Items]
Aggregate catastrophic loss coverage	562,700,000
Maximum single event coverage	420,400,000
Amount retained per Loss	7,000,000
Coverage afforded by FHCF	278,100,000
Percentage of FHCF coverage to total coverage (in hundredths)	49.40%
Reinsurance premium	21,700,000
Prepaid reinsurance premiums	$ 67,900,000