Investments (Details Textual) (USD $)	3 Months Ended	12 Months Ended
	Mar. 31, 2013 Securities	Dec. 31, 2012 Securities
Schedule of Investments [Line Items]
Number of fixed maturity securities classified as available for sale	88	46
Investments (Textual) [Abstract]
Percentage of which the company held security of any issuer	10.00%	10.00%
Fair value of fixed maturity securities classified as available for sale	$ 121,700,000	$ 72,200,000
Unrealized loss of fixed maturity securities classified as available for sale	2,100,000	825,168
Percentage decrease in value of individual equity security to assume other than temporary decline in value	20.00%
Time period for which individual security should be in unrealized position of twenty percentage or more to assume it as other than temporary decline	More than six months
Percentage of ownership interest	48.20%
Equity securities [Member]
Schedule of Investments [Line Items]
Number of fixed maturity securities classified as available for sale	5
General obligation bonds [Member] | Obligations of states and political subdivisions [Member]
Schedule of Investments [Line Items]
Aggregate fair value of bond held	352,200,000	358,500,000
Amortized cost of bond held	329,500,000	332,400,000
Special revenue bond [Member]
Schedule of Investments [Line Items]
Aggregate fair value of bond held	103,900,000	101,000,000
Amortized cost of bond held	$ 97,900,000	$ 93,900,000
Education bonds [Member]
Schedule of Investments [Line Items]
Percentage of investments in special revenue bonds	54.00%	54.00%
Water and sewer utility bonds [Member]
Schedule of Investments [Line Items]
Percentage of investments in special revenue bonds	16.00%	19.00%