Reinsurance Agreements (Details) (USD $)	3 Months Ended
	Mar. 31, 2015 Structure	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2014	Jul. 01, 2014
Reinsurance Agreements [Abstract]
Number of types of reinsurance structures	3
Liability for Catastrophe Claims [Line Items]
Prepaid reinsurance premiums	$ 46,039,000			$ 54,502,000
Percentage of quota share reinsurance treaty (in hundredths)	30.00%
Deferred quota profit share	8,800,000			10,500,000	14,000,000
Number of years quota share reinsurance treaty	2 years
Aggregate catastrophe coverage per year with maximum single event coverage	100,000,000
Aggregate cost of quota share is projected	6,700,000
Increase in total insured value		5,400,000,000	8,700,000,000
Percentage increase in total insured value (in hundredths)		8.20%	25.30%
Increase reinsurance premiums for total insured value		400,000	8,300,000
Percentage increase in reinsurance premiums for total insured value (in hundredths)			13.30%
Trust agreement for loss exposure	4,900,000			4,900,000
Florida [Member]
Liability for Catastrophe Claims [Line Items]
Aggregate catastrophic loss coverage	200,000,000
Aggregate catastrophic loss coverage of Florida	200,000,000
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
Aggregate catastrophic loss coverage of Florida	562,700,000
2014-2015 Hurricane Season [Member]
Liability for Catastrophe Claims [Line Items]
Aggregate catastrophic loss coverage	1,490,000,000
Maximum single event coverage	1,010,000,000
Reinsurance premium	40,200,000
Prepaid reinsurance premiums	117,000,000
Aggregate catastrophic loss coverage of Florida	1,490,000,000
2014-2015 Hurricane Season [Member] | Florida [Member]
Liability for Catastrophe Claims [Line Items]
Aggregate catastrophic loss coverage	1,460,000,000
Amount retained per Loss	11,200,000
Percentage of Florida coverage to total coverage (in hundredths)	98.50%
Coverage afforded by FHCF	546,300,000
Percentage of FHCF coverage to total coverage (in hundredths)	37.40%
Aggregate catastrophic loss coverage of Florida	1,460,000,000
2014-2015 Hurricane Season [Member] | Louisiana [Member]
Liability for Catastrophe Claims [Line Items]
Amount retained per Loss	$ 3,000,000