Schedule III - Supplementary Insurance Information (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Supplementary Insurance Information, by Segment [Line Items]
Deferred policy acquisition costs	$ 37,792,442	$ 34,425,593	$ 30,849,717
Loss and settlement expense reserves	610,180,850	583,096,965	593,300,247
Unearned premiums	220,627,284	196,215,465	180,689,377
Premium revenue	515,506,266	458,845,999	416,402,313
Net investment income	43,022,175	44,145,074	46,110,925
Losses and settlement expenses incurred	333,287,449	303,387,715	342,974,437
Amortization of deferred policy acquisition costs	94,727,668	84,274,773	77,318,057
Other underwriting expenses	65,754,441	60,918,591	54,515,442
Premiums written	534,076,700	478,481,485	429,787,492
Property and casualty insurance [Member]
Supplementary Insurance Information, by Segment [Line Items]
Deferred policy acquisition costs	32,740,088	30,872,124	28,342,752
Loss and settlement expense reserves	425,757,915	412,317,447	419,991,246
Unearned premiums	191,714,222	177,617,756	164,048,988
Premium revenue	392,718,848	357,138,686	321,649,215
Net investment income	31,396,676	32,214,705	33,718,436
Losses and settlement expenses incurred	260,917,009	233,892,280	251,449,247
Amortization of deferred policy acquisition costs	68,851,027	63,640,886	57,548,814
Other underwriting expenses	62,522,516	59,182,195	53,783,546
Premiums written	405,048,854	371,235,457	333,294,142
Reinsurance [Member]
Supplementary Insurance Information, by Segment [Line Items]
Deferred policy acquisition costs	5,052,354	3,553,469	2,506,965
Loss and settlement expense reserves	184,422,935	170,779,518	173,309,001
Unearned premiums	28,913,062	18,597,709	16,640,389
Premium revenue	122,787,418	101,707,313	94,753,098
Net investment income	11,634,972	11,940,123	12,395,350
Losses and settlement expenses incurred	72,370,440	69,495,435	91,525,190
Amortization of deferred policy acquisition costs	25,876,641	20,633,887	19,769,243
Other underwriting expenses	3,231,925	1,736,396	731,896
Premiums written	129,027,846	107,246,028	96,493,350
Parent company [Member]
Supplementary Insurance Information, by Segment [Line Items]
Deferred policy acquisition costs	0	0	0
Loss and settlement expense reserves	0	0	0
Unearned premiums	0	0	0
Premium revenue	0	0	0
Net investment income	(9,473)	(9,754)	(2,861)
Losses and settlement expenses incurred	0	0	0
Amortization of deferred policy acquisition costs	0	0	0
Other underwriting expenses	0	0	0
Premiums written	$ 0	$ 0	$ 0